The Infinitive as Predicate

The infinitive is used in predicates of several types, both nominal and verbal.

The Infinitive as Predicative

In the function of a predicative the infinitive is used in compound nominal predicates after the link verb to be:

His dearest wish was to have a son.

The subject of the infinitive predicative is either an infinitive or a noun. In either case the infinitive is used with the particle to. With homogeneous predicatives the use of the particle varies.

If the infinitives are not linked by conjunctions, the particle is generally used with all of them:

My intention was to see her as soon as possible, to talk to her, to calm her.

If they are linked by the conjunctions and ox or, the particle is generally used with the first infinitive only:

Your duty will be to teach him French and play with him.

His plan was to ring her up at once, or even call on her.

The use of the infinitive as a predicative has some peculiarities.

l) In sentences, with an infinitive subject the predicative infinitive denotes an action that follows the action of the subject infinitive.

To see her was to admire her.

To come there at this hour was to risk one's life.

Sentences in which both the infinitives are used without any modifiers are usually of aphoristic meaning:

To hear is to obey.

To see is to believe.

To define is to limit

The predicative function is generally performed by the common non-perfect active forms of the infinitive, although sometimes passive forms also occur:

To be born in poverty was to be doomed to humiliation.

2) The set of nouns that can function as the subject of a compound nominal predicate with an infinitive predicative is very limited. It includes about 50 nouns describing situations:

action	aim	attempt	consequence	desire
advice	ambition	business	custom	difficulty
duty	hope	job	plan	risk
experience	idea	method	principle	role
function	ideal	need	problem	rule
habit	instruction	object	purpose	task
happiness	intention	order	reason	wish and some others

Note l: As these nouns denote actions or states they are commonly used with determiners, pointing to the bearer of the action or the state denoted by them:

His intention was to get rid of the horse.

Her job is to come twice a week and clean the rooms.

Note 2: The noun thing may also perform the function of the subject of a predicative infinitive:

The best thing was to agree.

Note 3: A predicative infinitive may be introduced by the conjunctive adverbs and pronouns how, when, where, what, whom, the choice depending on the lexical meaning of the noun:

Now the question was what to tell him.

The problem was how to begin.

3)The function of the subject may be also performed by the pronoun all or the substantivized superlatives the most and the least with an attributive clause attached to them: ,

All he wanted was to be left alone.

The least I can expect is to have this day all to myself.

Note: In such cases the predicative infinitive can lose its marker to:

All I can do is get you out of here.

4) Occasionally the function of the subject can be performed by a gerund or a what-clause:

Living with hemophilia was to live off balance all the lime.

"What we want to do," said Brady, "is to fight a world."