82. Common Errors in Making Comparisons

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Quite a lot of grammar mistakes are commonly made when similarities or differences are being named

NATURE AND VARIABILITY OF COMPARISON

To compare is to point out similarities and/or differences. It is an important part of academic and professional writing (see, for example, 94. Essay Instruction Words and 115. Describing Numerical Data). Reflecting this importance, the grammar and vocabulary of comparison are quite varied (see 149. Saying How Things are Similar and 216. Indicating Differences).

Unfortunately, the variety of ways to compare means that numerous kinds of language error can be made by writers who are not used to English. Some of these are considered elsewhere within this blog, but the aim of the present post is to survey in a more complete way all of the aspects of comparison-making that seem to cause errors of grammar and vocabulary.
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COMPARISON ERRORS ALSO CONSIDERED ELSEWHERE

The following errors in comparison-making are considered in depth elsewhere within this blog.
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1. “On the Contrary”

This phrase is typically a “connector”, occurring in the second of two closely-related sentences to help show a meaning link between them (see 18. Relations Between Sentences and 40. Conjunctions versus Connectors). The error is to think that the meaning link is that of “difference” or “contrast”. The connectors that need to be used instead for this meaning are in contrast, by contrast or on the other hand (see 216. Indicating Differences).

The correct use of on the contrary is after a negative statement to show that its extreme opposite is meant rather than something halfway between negative and positive. Consider this:

(a) Paris is not at all far from London. On the contrary, it can now be reached by train in a little over two hours

Here, on the contrary says that not…far means “verty near”. For further discussion, see 20. Problem Connectors, #1.

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2. “Like” and “Unlike”

These words are the central topic of 56. Comparing with “Like” and “Unlike”. They must introduce a similar or different idea that the reader is expected to know already and hence is not the main point of their sentence. The error that can occur is using them before a main idea. Consider this:

(b) Ants form colonies headed by a queen, like bees.

This is a sentence about ants, not ants and bees. If the message is supposed to be as much about bees as ants, then a more appropriate wording instead of like bees might be and so do bees or, more formally, Both ants and bees … at the start (see 149. Saying How Things are Similar).

The distinction between ideas that are expected to be familiar to a reader and those that are not is common in comparison sentences, and can involve other wording than that considered here. It is, indeed, widespread in English as a whole (see 156. Mentioning What the Reader Knows Already).

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3. “The One(s)” versus “That/Those”

This is one of the points in the post 63. Constraints on Using “the one(s)”. Quite often there is a free choice between the one(s) and that/those, but in formal comparison-writing it is normal to use only that/those, like this:

(c) Deaths from road accidents are now much higher than those from malaria.

Using that/those is often necessary to ensure that a comparison is logically correct (see “Comparing Like with Like” in 170. Logical Errors in Written English).

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4. “Aspects” versus “Respects”

These two words both mean a “part” of an abstract idea like “a question”, “pity” or “life” (see 196. Saying what is inside Things). The choice between them depends on whether or not the preposition in is in front: after in, you have to say respects not aspects; otherwise aspects is the only possibility (see 81. Tricky Word Contrasts 2, #4). Saying *in…aspects is a quite common error by speakers who are not so familiar with English.

The need for in (and hence the common error) is particularly frequent in comparison-making because this preposition is the main means of saying how two things resemble or differ from each other (see #3 in the next section). Here is a typical sentence where in is followed by respects:

(d) Medicine and Veterinary Science differ/are similar in various respects.

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One other aspect of comparison-making that is considered elsewhere within these pages is not an error but should be mentioned because it can cause confusion. This is more before an adjective + uncountable or plural noun. The problem is that more can be understood as going with either the adjective or the noun, so that sometimes misunderstandings are likely (see 182. Structures with a Double Meaning 2, #3).

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FURTHER ERRORS IN MAKING COMPARISONS

The following are further possible errors with comparisons.

5. “Than” without a Comparative

English sentences with than usually need a comparative word in them – one with -er, more, less etc. (though American English also allows the non-comparative word different). Some other languages, by contrast, show comparisons only with a word like than – they do not require a comparative form with it. Speakers of such languages can easily forget to put an English adverb or adjective before than into the comparative form, producing such errors as *clear than or *quickly than (see 298. Grammar Meanings without Grammar, #3).

Note that compared to cannot accompany comparative words: it needs an ordinary adjective or adverb (see 231. Confusions of Similar Structures 3, #5). It also differs slightly in meaning from than (see 221. Multi-Word Prepositions, #3).

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6. Incorrect Prepositions

Some words indicating a similarity or difference are followed by a typical preposition that can be hard to remember (for the concept of “typical” prepositions, see 111. Words with a Typical Preposition). The underlined words in the following sentences are of this kind. What should the preposition be in each blank space?

(e) Greek cuisine is similar … Lebanese.
(f) Zambia has almost the same climate … Zimbabwe.
(g) Ford’s new model looks virtually identical … the old one.
(h) Winter in Russia is very different … summer.

The correct prepositions are to, as (not strictly a preposition but used similarly), to and from (than in American English). These are nearly always the only possible choices, except that some contexts require the same to have that rather than as (see 87. “Same As” versus “Same That”). Using of or with after any of the words is hardly ever correct.

Note that similar to, identical to and equivalent to can all be followed by a verb as well as a noun. The verb needs -ing because the to is a preposition (see 35. Words Followed by “to -ing”). Note also that no preposition is possible after the verb RESEMBLE (see 42. Unnecessary Prepositions).
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7. Inappropriate Clarification of a Similarity or Difference

The simplest kind of comparison merely indicates the existence of a similarity or difference. This is the case, for example, in sentence (e) above. However, such sentences can generally be expanded so as to say what the similarity or difference is. One way of doing this is with in. Thus, a continuation of (e) might be …in its common ingredients.

Even if the expansion needs a verb, you should still use in in formal contexts (not because). You can either add -ing to the verb to make a gerund, e.g. in using (see 70. Gerunds), or add that after in, like this:

(h) Greek cuisine is similar to Lebanese in that it uses substantially the same ingredients.

This use of in that is a rare example of that rather than the fact that after a preposition (see 153. Conjunction Uses of “that”). It is perhaps an indication that the two words together are actually a single conjunction (see 230. Multi-Word Conjunctions, #1).

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8. Excessive Use of “Less” before Nouns

Less can help to express a comparison before not just an adjective or adverb (less effective; less freely) but also a noun (less money). In the first case it is grammatically an adverb (see 194. Adverbs that Say How Much), in the second an adjective-like “determiner”.

The problem with the determiner use is that less is not the only word available – there is also fewer. Traditionally, there was a rule that less should precede uncountable nouns like money, fewer countable ones (in the plural form). Thus it was clear which should be used in the following:

(i) Jazz has … popularity today than in the past.

Because popularity is an uncountable noun, less is the right choice. By contrast, if countable fan was to be used instead of popularity, we would have to say fewer fans.

Today, however, the above rule is weakening. Many younger English speakers are using less all the time, the following noun remaining singular if uncountable and plural otherwise: less fans in (i). Some readers of formal writing may also accept this change, but it is not guaranteed. Thus, where the reader’s attitude is unclear, writers are safer following the traditional rule.

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9. Omission of “the” with Superlative Adjectives and Adverbs

It is quite a common error to omit the before a superlative adjective or adverb. However, to say that superlatives always need the is not fully accurate: most need it, one kind can keep or drop it, one kind typically drops it, and one kind replaces it with a(n).

The last of these possibilities is illustrated by the common marketing phrase a best buy. For a full explanation, see 305. Wording next to Superlatives, #3. Such combinations are not to be confused with usage like the following:

(j) A most interesting question was raised.

There is no superlative usage at all here because most means “very”.

When the rare need for a(n) does not arise, one common superlative type that always needs the is adjectives before a noun. One cannot, for example, say *hardest questions or *hardest of questions without the (for the difference made by of, see 247. Exotic Grammar Structures 6, #3).

Superlative adjectives after their noun, separated by a link verb like BE, also require the, provided their partner noun idea is being compared with other noun ideas rather than with itself in a different time or place (see below).

A third situation where the must be present is before a superlative adverb describing a following adjective:

(k) The most immediately RECOGNISABLE change was in colour.

The is not compulsory with two superlative types. With adverbs describing a verb rather than adjective, it can be kept or dropped without changed meaning:

(l) Those who TRIED (the) hardest were rewarded.

With adjectives after a link verb like BE, the is typically dropped to show a comparison with the same thing in another situation, e.g.:

(m) The police are busiest in summer.

This means the police are busier in summer than at other times. At their could be added before the superlative to make it even clearer (see 311. Exotic Grammar Structures 9, #3). Adding the, by contrast, would make the comparison with other workers.

For more about superlatives, see 194. Adverbs that Say How Much and 305. Wording next to Superlatives. For more about the, see 235. Special Uses of “the”.

81. Tricky Word Contrasts 2

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Some pairs of words are easily confused because of close similarities in spelling and/or meaning

THE PROBLEM OF TRICKY WORD CONTRASTS

Most users of English have encountered vocabulary items that are easily confused because they resemble each other in spelling and/or meaning. Some of these – for example principle/principal – are particularly well-known because they are often explained in English language coursebooks. However, many others are not found there and can remain unexplained and sometimes not even recognised.

It is vocabulary pairs like this, especially ones that are likely to occur in professional writing, that are the focus of the present post, just as they are of various others with a similar title (see the “Posts on Specific Words” page for a complete list). Other Guinlist posts that deal with vocabulary confusions include 16. Ways of Distinguishing Similar Words,  44. Troublesome Prepositional Verbs,  94. Essay Instruction Words and 211. General Words for People.

For some grammar confusions, see 129. Differences between Necessity Verbs, 133. Confusions of Similar Structures and 217. Tricky Grammar Contrasts. For some pronunciation ones, see 144. Words that are Often Heard Wrongly.
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LIST OF CONTRASTS

1.  “Responsively” versus “In Response”

English resembles various other languages in possessing numerous adverbs which, like responsively, can be made into a similar-looking preposition phrase. In most cases, such pairs are very similar in meaning, the distinguishing factor being something other than meaning, such as sentence position (see 85. Preposition Phrases and Corresponding Adverbs). However, responsively does differ significantly in meaning from in response, and is hence sometimes misused.

In the majority of cases, in response is likely to be the correct choice. It just shows that an utterance is a response to something external to the speaker – usually the words of another person. Responsively, by contrast, indicates more than this. The primary meaning of its related adjective responsive is “willing and quick to respond”, and this idea of rapid, willing response is carried over into the adverb.

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2.  “On the Top of” versus “On Top of”

The first of these, with the, just conveys the basic meaning of top, namely “highest part”, and is typically found before physical top-possessing ideas like a hill or a cake. The use without the could still communicate the same meaning (on top of a hill), but it could alternatively mean “in addition to”, as in:

(a) The claimant suffered personal injury on top of financial loss.

This is an example of a metaphorical meaning (see 229. Metaphorical Prepositions), also expressible with besides. On top of seems more easily classifiable as a multi-word preposition than on the top of. For further idiomatic contrasts involving the, see 235. Special Uses of “the”, #8.
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3.  BE SUPPOSED TO versus BE INTENDED TO

These passive verbs can both help to name the purpose of something, but supposed is negative, suggesting that the purpose is unlikely to be achieved. A typical sentence might be:

(b) Parking charges are … to discourage car use.

Supposed here would express scepticism about the ability of parking charges to achieve their purpose, whereas intended would merely state the purpose without indicating any opinion. A synonym of intended would be aimed at (+ -ing: see 226. Words with Complicated Grammar 2, #3). Instead of supposed, one could say meant. For more words that suggest falseness of an idea, see 319. Superficiality. For more ways of expressing a purpose, see 60. Purpose Sentences with “for”.

A tricky feature of both verbs is that their meanings change when they become active instead of passive. SUPPOSE loses its purpose-indicating meaning completely and becomes more like BELIEVE. INTEND still expresses a purpose, but differently from AIM (see 114. Tricky Word Contrasts 3, #5 and 195. Tricky Word Contrasts 7, #2).

Moreover, the “believe” meaning of SUPPOSE can also be expressed by BE SUPPOSED TO. Indeed, sentence (b) could be understood in this way (“People believe that parking charges discourage…”). This means SUPPOSE needs to be treated with special care.
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4.  “Aspects” versus “Respects”

Aspects usually refers to parts or components of an abstract idea like “problem”, “love” or “behaviour” (see 196. Saying what is inside Things). However, respects is preferred to express a similar meaning in one specific but common situation. Consider this:

(c) Einstein modified Newton’s theory in various respects.

The message here is that various parts of Newton’s theory were modified. The reason why respects is preferred to aspects is nothing more than the preposition in. This preposition seems always to rule out the use of aspects after it, and respects seems always to require it. However, ways is sometimes preferred to respects.

A context where in…respects is particularly likely to be found is comparisons, e.g. differs in some respects or is greater in three respects (see 82. Common Errors in Making Comparisons).
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5.  “Effect” versus “Affect”

This confusing pair is sometimes explained in coursebooks. The first, beginning with “e”, is mostly a noun meaning “an impact”. It can be used alone, e.g. The effect was …, or combined with HAVE to express an action (see 116. Rarer Uses of HAVE):

(d) Climate has a great effect on culture.

Affect, beginning with “a”, is a verb meaning “cause to be different”. It too could be used in (d): the underlined words could become greatly affects. Changing the adjective great into the adverb greatly recognises that affects is a verb and not a noun (see 120. Six Things to Know about Adverbs, #2).

Adding to the confusion, effect (with “e”) is also a verb meaning “cause to happen”. For example, effecting a change is causing a change to happen. Contrast this with affect a change, which would mean “cause a change to be different”.
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6.  “Underline” versus “Underlie”

It is easy not to notice the second “n” in underline. This word means “draw a line under”, or (metaphorically) “emphasise”. Without “n”, the meaning is basically “be under” or, metaphorically, “cause” (see 306. Ways of Giving a Reason, #3). The cause is usually implied to be hidden. Here are the two words in use:

(e) The road accident rate underlines (emphasises) the need for lower speed limits.

(f) Excessive salt intake often underlies (invisibly causes) high blood pressure.
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7. “Failure(s)” versus “Failing(s)”

Failure is a noun that can express the same action meaning as the verb FAIL (“the action of failing”), being then what I call an “action” noun:

(g) Failure to follow this advice may result in serious accident.

As the absence of any word before singular failure here shows, this use is, like that of most action nouns, uncountable (see 14. Action Outcomes). Also like most action nouns, it is replaceable in sentences like (g) with the “gerund” (-ing) form of the verb, failing (see 131. Uses of “Action” Nouns). This gerund is not the same as failing(s) above because, like any gerund, it cannot be made plural (see 240. Nouns that End with “-ing”).

When failure is an action noun it can, like the verb FAIL, link with a following to (infinitive) verb – failure to follow above (see the end of 239. Noun Phrases Made with a “to” Verb).

A further feature of many action nouns that failure shares is ability to be used in a countable way to refer to something associated with the relevant action, namely a person or project that has failed (see 19. Activity Locations):

(h) The first attempts to fly were failures.

By contrast, the noun failing only has a countable use, and never expresses the action meaning of the verb FAIL. It means “weakness” or “flaw”. One might say, for example, that a person or a project had a major failing or many failings.

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8.  “Plant” versus “A Plant”

Many nouns have both a countable form (usable with a or plural -s) and an uncountable form (not usable with a or -s), the meaning being slightly different in each case (see 14. Noun Countability Clues 1).

The noun plant, however, has completely different meanings in its countable and uncountable forms, suggesting they are actually two different words with the same spelling (see 6. Homonyms and Homographs), rather than different uses of the same word. Uncountable plant means “heavy machinery” while countable a plant usually means the familiar “growing botanical organism”.

Complicating matters further is the fact that a plant occasionally has an alternative meaning, again completely different from the others: “building or buildings devoted to an industrial process”, as in a nuclear power plant or a bottling plant.

Another word with very different countable and uncountable meanings is company. The countable form a company means a commercial business, whereas uncountable company means people who are with somebody.

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9.  “Amount” versus “Number”

These two nouns often accompany of and another noun, as in a large amount of money. The choice between them depends on the countability of this other noun: number with countable nouns (generally plural), amount with uncountable ones.

With no following of, the noun determining whether to use amount or number will usually be earlier:

(i) A crowd of people stood outside. A large number were shouting.

(j) Alcohol in moderation can be beneficial. Large amounts, however, are harmful.

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10.  “Concern(ed) With/About/For”

The meanings of concerned change according to the preposition. Concerned with means “involved” or “associated” (e.g. problems concerned with driving). In this case, concerned is a “past” participle of the verb CONCERN.

On the other hand, concerned with either about or for is an adjective meaning “worried” (see 245. Adjectives with a Participle Ending). The prepositions make slight modifications to this basic meaning. It is not unusual for a single adjective meaning to be closely associated with different prepositions in this way (see 134. Words with a Variable Preposition, #1).

The choice between about and for depends mainly on whether the noun after them names a bad situation (e.g. drug abuse) or its sufferer (e.g. drug abusers):

(k) Most doctors are concerned about drug abuse.

(l) Most doctors are concerned for/about drug abusers.

If there is a difference between the prepositions in (l), it is perhaps that for suggests worry about the future welfare of the people mentioned after it, whereas about links the worry more with what they are doing now.

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11.  “Editor” versus “Publisher”

Editors make judgements about the content of publications – what is said, how it is said, and (when there are multiple authors) who says it and in what order. In a bibliography, an editor is named only when reference is being made to an article in a multi-author book (see 197. The Language of Bibliographies). The name is normally recognisable from the abbreviation (ed.) – plural (eds.) – written after it (see 130. Formal Abbreviations).

Publishers, on the other hand, are companies that make publications available to the public. They are responsible for all aspects of producing a publication, including the hiring of editors. In a bibliography, publishers’ names are given for all books but not for periodicals. They are usually positioned after a book’s title.

80. How to Paraphrase

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Write paraphrases without looking at the source text, and avoid synonym-substitution

DEFINITION AND USES OF PARAPHRASE

To paraphrase is to change one’s own or someone else’s wording without changing what it means. The related noun paraphrase may be uncountable, meaning “making a paraphrase”, or countable, meaning “paraphrased wording” (see 14. Action Outcomes). The idea of changing “wording” should not be confused with that of changing “words”. Wording involves not just words but also word order, sentence structure and sentence divisions (see 236. Tricky Word Contrasts 9, #5). It is possible, for example, to paraphrase one sentence as two or just a part of one.

Paraphrase is useful in various ways. One that is familiar to many students is reporting (with a suitable academic reference) what another writer has said. This is an alternative to quotation, and much more common, being preferred unless there is a good reason for keeping the exact original, such as clever, concise or ambiguous wording (see 79. Fitting Quotations into a Text and 127. When to Use Indirect Speech).

Other uses of paraphrase relate to one’s own wording rather than someone else’s. We might want to modify what we have written to reduce its word count or to make it sound better (e.g. less repetitious or more formal: see 265. The Importance of Grammar in Writing). We might want to repeat something with a paraphrase to assist the reader’s understanding (see 286. Repeating in Different Words). In speaking, when we are uncertain about a particular word or grammatical structure, paraphrasing it enables it to be avoided altogether. Doing this may be fundamental to the successful acquisition of a new language (see 202. Some Strategies for Learning English, Practice Strategy #2).

Successful paraphrase has two major requirements: keeping faithful to the original meaning and changing the wording in the right way. This post offers advice in both of these areas.

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THE DANGER OF CHANGING THE MEANING

The fundamental requirement for preserving the exact meaning of a source text is to properly comprehend it. This seems obvious, but is sometimes forgotten because paraphrase is generally thought of as a writing skill rather than a reading one. All of the reading posts within this blog are useful towards this end, but one that I would single out for special mention here is taking account of every word in a text, recognising that not doing so can drastically alter the understood meaning (see 15. Half-Read Sentences). What this means for paraphrases is that they must convey the meanings of all the words in the source text (and no extra ones).

It is also important to prevent our expectations about a topic from blinding us to what a source text actually says. Expectations have a very powerful effect on our perceptions. Consider the following sentence and its supposed paraphrase:

(a) Physical strength differs in men and women.

(b) Men are physically stronger than women.

Sentence (b), the attempted paraphrase, speaks of something that is not present in (a): the greater physical strength of men. All that sentence (a) mentions is a difference of physical strength, leaving it unclear whether men are stronger than women or women are stronger than men. The likelihood is that someone paraphrasing (a) with (b) has done so because the topic of gender strength always triggers thoughts of greater male strength, and these thoughts have blinded them to what (a) actually says.

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STEPS IN PARAPHRASING

The main paraphrase steps might be listed as (1) Read and understand, (2) Remove the source text, (3) Try to recall what has been understood, and (4) Put the recalled message – not the words – into writing. The main problem is escaping from the original words.

A key factor is the length of the original text. If it is great, the exact wording will almost certainly disappear at the recall stage, since remembering its message will take up all of our mental capacity¹. Even if we make notes on a long text to help us remember it, we should still be able to derive a good paraphrase from them because notes are of their nature so different from continuous prose (see 158. Abbreviated Sentences).

On the other hand, if the original text is very short, remembering its wording is much more likely. It is this problem of paraphrasing still-remembered wording that I  want to focus on here, not least because suggesting a solution involves discussing grammar and vocabulary. The starting point is the importance of not simply replacing individual words with suitable synonyms.

There are two good reasons for avoiding synonym-substitution. The first is that it does not prove comprehension of the source text: anyone can use a translation dictionary to find a synonym of a particular word in a text they do not understand. The second problem with synonym-substitution is that it easily results in inaccurate paraphrase or incorrect-sounding English, because synonyms are rarely exactly equivalent to each other (see 5. Repetition with Synonyms and 16. Ways of Distinguishing Similar Words).

One common feature of good paraphrase is word substitutes that differ not so much in their spelling as in their grammatical class. Consider the following sentence and possible paraphrase:

(c) Jazz has always been popular.

(d) Jazz has never lost popularity.

Changing the adjective popular into its related noun popularity has other effects on the sentence. The verb been in (c) becomes no longer logical and needs to be exchanged for one that is. There are various possibilities, such as kept and enjoyed, but I have preferred the very typical partner verb lost, changing always into never to accommodate it. For more about typical partner verbs, see 273. Verb-Object Collocations.

Another way to paraphrase without simple word substitution is to reposition words in a sentence. For example, sentence (c) could be rewritten with the idea of “popular” at the start. Since adjectives rarely start sentences, it is easier again to use popularity, producing The popularity of jazz…. There are various ways of continuing: …has always existed or …has never been lost or …has been constant. I prefer the last because it is briefer and uses an adjective (constant) to paraphrase an adverb (always).

A third type of paraphrase expresses a grammatical meaning in a non-grammatical way (or vice versa). Grammatical meanings are typically expressed either by letters added to words, such as comparative –er and plural -s, or by words considered by grammarians to belong more to grammar than to vocabulary, such as than or so that or because of. An example of this kind of substitution is replacement of -er by relatively, as in relatively large instead of larger. For a range of possibilities in this area, see 298. Grammar Meanings without Grammar.

These three types of paraphrase – changing word classes, changing sentence positions and changing grammatical expressions – provide a blueprint for paraphrasing short texts acceptably. This is to start by asking for each type which words in the text it might be applied to. Actually thinking out how individual words might be changed is very likely to suggest how the rest of the sentence could be worded.

In addition to trying to create paraphrases, reading ready-made ones may be a helpful strategy. In this blog there are plenty of examples. Particularly notable posts in this respect are on examples,  passive verbs, consequences, similarities, differences, importance, time duration and exceptions. There are also posts on finding alternatives to prepositions and adjectives.

To gain some appreciation of how able you already are to paraphrase in the appropriate way, try the following practice exercise.

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PRACTICE EXERCISE (SENTENCE-LENGTH PARAPHRASE)

Each question in this exercise presents one complete sentence and the beginnings of three paraphrases. Ways of finishing the paraphrases are suggested afterwards. For further practice, see 312. Grammar Command Test 3 (Rewriting).
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1. Physics and Chemistry have certain similarities.
(a) Physics is …
(b) Certain …
(c) There are …
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2. Very few people live for more than 100 years.
(a) Living …
(b) The number …
(c) The human life span…
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3. It is many years since the moon landing.
(a) Since …
(b) The moon …
(c) There has not …
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4. The greatest challenge in note-taking is identifying main ideas.
(a) There is no greater …
(b) Note-taking …
(c) It is particularly …
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Suggested Answers (alternatives are possible)
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1(a) Physics is similar to Chemistry in certain respects (not “aspects” – see 81. Tricky Word Contrasts 2).
1(b) Certain similarities exist between Physics and Chemistry.
1(c) There are certain similarities between Physics and Chemistry.
2(a) Living beyond 100 years is very unusual.
2(b) The number of people who live beyond 100 years is very small.
2(c) The human life span very rarely exceeds 100 years.
3(a) Since the moon landing, many years have passed.
3(b) The moon landing happened many years ago.
3(c) There has not been a moon landing for many years.
4(a) There is no greater challenge in note-taking than identifying main ideas.
4(b) Note-taking presents no greater challenge than identifying main ideas.
4(c) It is particularly challenging in note-taking to identify main ideas. (see 103. Commenting with “It” on a Later Verb)

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¹See Bransford, J.D. and Franks, J.J. (1971).  The Abstraction of Linguistic Ideas. Cognitive Psychology 2, 331-350.