Beware of thinking that a noun can go before a “to” verb just because its related adjective can. A preposition might be needed instead of “to”.
A FAMOUS ERROR WITH “to”
This post is about a very common error made by writers and speakers whose mother tongue is not English. Readers are invited to identify it in the following example:
(a) *Rockets provide the possibility to travel in outer space.
The error is using a to verb (here to travel) after possibility to specify what the possibility is. It can be corrected by saying either possibility of travelling or chance to travel (see 181. Expressing Possibility). In general, when possibility needs to be specified by means of a following verb, the only alternative to of + -ing is a statement beginning with that (see 153. Conjunction Uses of “that”). A to verb is always wrong after possibility except in the following use:
(b) Travelling by train is the best possibility to choose.
This use of to is allowed after practically any noun. It means “that we should …”.
One probable reason for the error with possibility is the normality of using a to verb after the related adjective possible – there is no problem saying possible to travel. Another reason is probably the fact that various similar-seeming nouns (e.g. chance, ability, potential, will) easily take the infinitive (see 140. Words with Unexpected Grammar 2, #e).
In this post I wish to present a list of nouns that, like possibility, cannot combine with a to verb as their related adjectives can. Since their correct use involves a preposition, the post fits into the general category of preposition usage, all of whose posts can be viewed by clicking on “prepositions” in the CATEGORIES menu to the right of this page.
ADJECTIVES POSSIBLE WITH “to” WHOSE NOUNS ARE NOT
Many adjectives can go with a to verb. Quite often the nouns related to these adjectives can as well, but not always. Is there any way of discovering when an adjective has a related noun that does not allow to? Some indication may in fact be gained by placing the adjective and its following to verb after BE in a sentence like this:
(c) The Romans were keen to learn from the Ancient Greeks.
(d) Other galaxies are impossible to reach.
These two adjectives differ in the kinds of subject they give to the to verbs. In (c), the subject of to learn is the same as the subject of the main verb of the sentence (were), namely the Romans. In (d), however, the subject of to reach is not the main verb’s subject (other galaxies), but the unmentioned idea of human beings. There is more about this difference, including some further guidelines for discovering which adjectives are like keen and which are like (im)possible, in the post 83. Active Verbs with Non-Active Meanings (2).
This difference between keen and impossible seems to be a good (but not totally reliable) indication of whether or not to will be usable after an adjective’s related noun. It will be usable when the adjective is like keen (keenness to learn) but not when the adjective is like impossible (the impossibility of reaching).
Here is a list of adjectives like (im)possible. The corresponding nouns – which cannot usually have a to verb after them – are listed in the next section, but before reading those it might be a useful vocabulary exercise to try and predict them here.
ACCEPTABLE, APPEALING, CHALLENGING, COMPULSORY, CONVENIENT, DANGEROUS, DESIRABLE, DIFFICULT, EASY, HARMFUL, HAZARDOUS, IMPORTANT, IMPOSSIBLE, NECESSARY, PLEASANT, POINTLESS, POSSIBLE, PROBLEMATIC, PROFITABLE, RISKY, SUITABLE, UNNECESSARY, USEFUL, USELESS, VALUABLE
Two further examples of how these combine with an infinitive in a sentence are:
(e) Kuala Lumpur is easy to visit.
(f) Japanese is useful to know.
NOUNS NOT POSSIBLE WITH “to”
The noun forms of the above listed adjectives are:
ACCEPTABILITY, APPEAL, A CHALLENGE, COMPULSORINESS, CONVENIENCE, DANGER, DESIRABILITY, DIFFICULTY, EASE, HARM (and HARMFULNESS), A HAZARD, IMPORTANCE, IMPOSSIBILITY, NECESSITY, PLEASURE[i] (and PLEASANTNESS), POINTLESSNESS, A POSSIBILITY, A PROBLEM, PROFIT (and PROFITABILITY), RISK (and RISKINESS), SUITABILITY, UNNECESSARINESS, USEFULNESS, USELESSNESS, VALUE
A verb giving more detail about one of these nouns cannot normally be in the to form, but must be used with a preposition instead. The choice of preposition depends on the noun (a common preposition property – see 111. Words with a Typical Preposition), but the right preposition will often be of:
(g) The ease of visiting Kuala Lumpur is mentioned by most travellers.
(h) Business people recognise the usefulness of knowing Japanese.
A different preposition, in, is normal after there is, but only some of the nouns can be used with there is. They include APPEAL, A CHALLENGE, CONVENIENCE, DIFFICULTY, HARM, A PROBLEM, PROFIT, RISK, USEFULNESS and VALUE. The kind of sentence in question is:
(i) There is appeal in travelling abroad.
For more about sentences like this, see 161. Special Uses of “There” Sentences.
One other noun usable after there is is A POSSIBILITY, but it still takes of rather than in (see 181. Expressing Possibility). The use of DANGER and RISK is also noteworthy: with the uncountable form, one says there is danger/risk in X (meaning X involves danger/risk), but with the countable form there is a danger/risk of X (meaning X is a possible bad consequence). The variable countability of danger and risk is of the kind discussed in the Guinlist post 43. Noun Countability Clues 4: Substance Locations.
An alternative to of + -ing after POSSIBILITY, DANGER and RISK is that + ordinary verb (see 153. Conjunction Uses of “that”).
CURIOSITIES AND EXCEPTIONS
The following nouns seem to behave peculiarly.
DIFFICULTY and PROBLEM sometimes have with instead of of. This seems to be when the meaning is “belonging to”, as opposed to “which is”. Compare:
(j) The difficulty with driving electric cars is the time needed to recharge their batteries.
(k) The difficulty of driving electric cars is not well known.
Sentence (j) suggests that electric cars are not difficult in all respects, but just in the mentioned one, while (k) indicates that electric cars are difficult in general. A further point to note is that with can be left out altogether, especially when problem/difficulty is the object of another verb, like this:
(l) The police have a problem (with) controlling drug use.
For other nouns with alternative following prepositions, see 134. Words with a Variable Preposition.
INTENTION, CONDITION and CAPABILITY resemble the nouns in the main list above in needing of, but are unusual in that even their adjectives (INTENT, CONDITIONAL and CAPABLE) are followed by prepositions + -ing (on/upon, on/upon and of respectively) rather than a to verb.
NECESSITY and DUTY seem to allow both of doing and to do, though they prefer to do when they follow a (with or without there is at the start). The adjective NECESSARY is also slightly unconventional: although it takes to, you must normally put it after it is, like this:
(m) It is necessary to consider the possible outcomes. (NOT *The possible outcomes are necessary to consider).
DUTY has no exactly corresponding adjective (dutiful is a slightly different kind), but the noun can be used like an adjective after it is in the same way as necessary (it is a/everyone’s duty … ). For more about this use of it, see 103. Postponed Subjects in “It” Sentences.
[i] It is important to distinguish between the pleasure of (doing) and a pleasure to (do). The latter is common after it is in speeches to show appreciation of something you are doing.