The functions of the infinitive in the sentence
The infinitive can be used in different syntactic functions:
1.The infinitive as a subject. In this function it may precede or follow the predicate. In the latter case it is introduced by the introductory it:
e. g. To speak with her was a real pleasure.
It was a real pleasure to speak with her.
2. The infinitive as a predicative (usually after the link verb to be):
e. g. My habit is to get up early.
To see her is to admire her.
What we want to do is to help our friends.
The question was difficult to answer.
3. The infinitive as a part of compound verbal predicate:
a) with modal verbs, modal expressions:
e. g. The train was to leave at midnight.
b) with phasal verbs (verbs denoting the beginning, duration, repetition or end of the action, such as to begin, to start, to cease, to continue, used to, would, etc.):
e. g. They gradually ceased to talk.
c) in Subjective Infinitive Construction;
e. g. He seems to have proposed to Mary.
4. The infinitive as an object:
after the verbs to advise, to allow, to ask, to compel, to order, to persuade, to recommend, to tell, to teach, to promise, to want:
e. g. He promised to come in time.
b) after some adjectives and statives (anxious, glad, happy, proud, amused, horrified, surprised, pleased):
e. g. I’m ready to help him.
c) after the verbs to find, to consider, to believe, to think. In this case the infinitive is preceded by the introductory object it:
e. g. I find it impossible to leave the spot.
5. The infinitive as a part of complex object:
e. g. I never saw you act this way before.
6. The infinitive as an attribute can modify:
a) both abstract and concrete nouns:
e. g. I have no desire to go there.
b) the noun-substitute “one”:
e. g. He is the one to be trusted.
c) pronouns ending in –body, -thing, -one:
e. g. She is someone to admire.
d) ordinal numerals:
e. g. He is always the first to come.
e) such adjectives as next, last, much, little, little more, enough:
e. g. I’ve got no more to add.
7. The infinitive as adverbial modifier:
a) of purpose (often with in order to, so as not to):
e. g. I stopped for a minute in order to rest.
I went to London to learn English.
of result (chiefly occurs after enough and too, so+adj.+ as, such+noun+as):
e. g. He didn’t run fast enough to catch the train.
He is so kind as to help me.
She is not such a fool as to think you innocent.
of attendant circumstances:
e. g. She rushed home to find a thief exploring the house (= She rushed home and found a thief exploring the house).
d) of condition:
e. g. To look at his pictures you would have thought that Monet (= If you had looked…)
she would be unhappy to marry for money (= If she married for money…).
of time:
e. g. She was surprised to learn how much he’d spent (= when she learnt).
f) of exception (after prepositions but or except):
e. g. She does nothing but grumble.
g) of comparison (with conjunctions as if, as though):
e. g. Her lips moved as if to warn me.
8. parenthesis:
To begin with, to be more precise, to be sure, to crown it all, to cut a long story short, to put it mildly, to say the least, to say nothing of, to sum it up, to tell the truth:
e. g. To tell the truth, I don’t really like her.