Active and passive verb forms can be confused in a variety of ways for a variety of reasons
TYPES OF PASSIVE VERB ERROR
Verbs are usually made passive by being given the “past participle” ending (-ed or irregular equivalent – see 52. Participles Placed Just After their Noun) and placed after some form of BE. Examples (with the BE part underlined) are was helped, is understood, were being copied, can be taken and should have been known. Sometimes BE is replaced by BECOME or informal GET, e.g. got taken. Meanings of the passive form are discussed in this blog in the posts 21. Active Verbs with Non-Active Meanings 1 and 66. Types of Passive Verb Meaning.
Errors with passive verbs are, like all grammar errors, either impossible word combinations or possible ones that do not express the required meaning (see 100. What is a Grammar Error?). An example of the former is:
(a) *Following discussion, objectives will be generate.
The underlined words are not a possible combination because they do not follow the general grammar rule that verbs after BE need either -ing or -ed (see 140. Words with Unexpected Grammar 2, # [f]). The correct choice in this case is, of course, the passive ending -ed.
Passive verb errors comprising possible word combinations are of two main kinds: either the verb made passive when it should be active, or an active used when a passive is needed. These may be illustrated as follows:
(b) *Malaria victims are suffered high body temperatures.
(c) *After much discussion, three main objectives generated.
In (b), are suffered is recognisable as a passive verb, but is incorrect both meaning-wise (the meaning of the active form is needed) and grammar-wise (as a passive. it cannot have a directly-following noun). In (c), generated is recognisable as an active verb (in the past simple tense), but again is incorrect in both grammar and meaning.
Note that using a passive form where grammar and meaning allow one – for example were generated in (c) – is never incorrect, however awkward or excessively formal it might seem. The problem is then one of style rather than grammar (see 27. How to Avoid Passive verbs and 69. How Computers Get Grammar Wrong 2).
Each of the above error types can be explained in a different way – and indeed may have more than one possible explanation. In this post I aim to explore some possible causes of error in the choice between active and passive verb forms, my hope being that readers who do not yet possess full accuracy in this area may be helped to attain it more rapidly.
CAUSES OF PASSIVE VERB ERRORS
1. Mother Tongue Influence
Differences between a learner’s mother tongue and English are perhaps not the greatest cause of active/passive errors in English, but they are probably one. A likely influence may be on to verbs after adjectives like ready and useful, which some other languages make passive but English mostly makes active (useful to know – see 83. Active Verbs with Non-Active Meanings 2). The error would thus be passives where actives were needed – another form of (a) above.
2. Poor Command of the Passive Form
Poor command of the way passive verbs are made is probably the simplest cause of passive verb errors. It exists when a writer or speaker has chosen to use the passive voice but fails to produce an accurate passive form.
One possible reason for such a failure is a misunderstanding about how exactly passive verbs are made in English. However, a more likely reason is that the correct form of the passive has not yet been learned strongly enough to be recalled quickly under the pressure of real-time communication. In other words, the speaker or writer will have knowledge of the correct form but not skill in using it (see 138. Test Your Command of Grammar for more on this distinction).
Poor command of the passive form could explain the errors in both (b) and (c) above. In (b), generated could be an intended passive verb to which the writer has failed to add the necessary BE part. If this was the case, the -ed would be that of the “past participle” rather than the similarly-spelt past simple active tense (we cannot tell which it actually is because both of these forms are the same in regular verbs like GENERATE).
In (c), if a passive verb is being sought, the error is an absent -ed. If lack of skill does not explain this kind of form error, incorrect knowledge caused by the way English works elsewhere might very easily. One influence could be the tendency of -ed endings to be pronounced so weakly in spoken English as to be barely heard (see 144. Words that are Often Heard Wrongly).
Another possible influence is the ability of some verb spellings, such as open, to be an adjective as well, and so to be usable after BE without an ending – is open as well as is opened (see 66. Types of Passive Verb Meaning). Such adjectives will inevitably be mistaken for verbs sometimes, and could then easily generate the belief that -ed can be dropped from any passive verb, leading to its absence from verb-only spellings like generate. More on this confusion is in the post 133. Confusions of Similar Structures (#8).
3. Misunderstanding of a Passive Verb’s Meaning
Example (a) above might illustrate this problem. Superficially, the use of the passive are suffered seems to be another type of poor grammar command: choosing the passive in the wrong grammatical context (directly before the noun high body temperatures without a preposition in between). However, I believe that a misunderstanding of the meaning of the passive may be the real problem, causing the grammatical context to be ignored. Another example might be:
(d) *Water is filled (= “is poured into”) the tank.
The problem with the meanings of SUFFER and this use of FILL is that their active forms already express a passive meaning. If learners of English have been led to believe that passive meaning must always expressed with a passive verb, the above unnecessary uses of the passive must sometimes inevitably occur. The correct use of BE SUFFERED is after the cause of suffering – high body temperatures in (a) – not its recipient. Other verbs whose active form has a passive meaning at least some of the time include HAVE, RECEIVE, MEET and SEE. For more details, see 21. Active Verbs with Non-Active Meanings 1.
4. False Belief about a Verb’s Grammatical Properties
As suggested above, the error in sentence (b) above is not necessarily an intended passive verb gone wrong – it could be an intended active form (in the past simple tense) of a verb that should be passive.
There is a very good reason why the active form of GENERATE might seem possible in (b) to someone lacking deep familiarity with English: some synonyms of GENERATE would actually be possible in the active voice. There would be no problem, for example, with developed. The reason is that DEVELOP is one of those verbs that can be active regardless of surrounding word order (see 4. Verbs that Don’t Have to be Passive). The inability of GENERATE to be used like this is not predictable in any way from its meaning – you just have to discover and memorize which verbs have which abilities.
The power of synonyms to affect grammar choices is extensively analysed within this blog in the posts 10/140. Words with Unexpected Grammar 1/2. The problem, those posts point out, is that although synonyms do often follow the same grammar rules, exceptions are very common and cause numerous errors. The error above with generated may be one of those. It is true that GENERATE does also have synonyms that could not be used in the active voice in (b), such as OBTAIN or REACH. However, it will not be obvious to learners of English why GENERATE should be like them rather than like EMERGE or DEVELOP.
While the false grammatical belief behind (b) could be that an impossible active form is possible, the reverse – that an impossible passive is possible – might explain some errors like that in (a). Consider this:
(e) *Numerous problems are remained.
The verb REMAIN is of the kind that cannot ever be passive. The false belief that it can be might result from the possibility of using the synonymous passive are left. Note that (e) is like (a) only in containing a passive that should be active. A major difference is that SUFFER in (a) does not always have to be active: it can be passive in the right circumstances.
Another always-active verb that is easily used wrongly in the passive is CONSIST OF, like this:
(f) *Water is consisted of hydrogen and oxygen.
In many cases, the reason for a false belief about a verb’s grammar is probably simple uncertainty arising from the sheer unpredictability of verb properties. However, here, as with GENERATE, there is again a probable influence from the grammar of other verbs with a similar meaning. Both is composed of and is comprised of mean the same as consists of despite their passive forms. Even more confusing is the fact that COMPRISE can also, unusually, be used in the active voice in (f) (comprises without of). More about COMPRISE can be read in both 21. Active Verbs with Non-Active Meanings 1 and 42. Unnecessary Prepositions.