As a predicative after a link verb.

e. g. The greatest wealth is to live content with little,

for there is never want where the mind is satisfied. (Lucretius).

One duty is to be useful, not according t our desires, but according to our powers. (H. F. Amiel)

The only way to get the best of the argument is toavoid it. (Dale Carnegie)

A true businessman’s absolute fundamental aim isto make money out of satisfying customers. (Author Unidentified).

The object of a good general is to fight but to win. (The Duke of Alva)

 

3. As a part of a predicative after the following expressions: to be afraid, to be angry, to be astonished, to be delighted, to be glad, to be eager, to be happy, to be pleased, to be ready, to be sorry:

e. g. I was ready to hear such news but, anyway, I was shocked.

4. As a part of a simple verbal predicate in negative and interrogative sentences:

e.g. Do you see that strange object in the sky?–– I don’t. I don’t see anything except billions of stars and the yellow piece of cheese–– the Moon.

Note: It’s necessary to point out that there is a point of view that sometimes the infinitive may function as a simple verbal predicate, for example in the sentences of the following type:

e. g. Me–– to marry you?

Why (to) go there?

5. As a part of a compound verbal modal predicate:

In this function the infinitive can follow:

a). Modal verbs proper: can, may, must, to be to, to have to, shall will, should, would, ought to, need, dare

e. g. A great mistake you can make in life is to be continually thinking that you are always right. (Anonymous.)

Grief can take care of itself, but to get the full value of joy you must have somebody to divide it with.

b). Verbs with modal colouring (ones expressing modality): to hope, to intend, to mean, to suppose, to try, to think, to want, to wish.

e. g. A classic is something that everybody wants to haveread and does not want to read. (Mark Twain).

c). Modal expressions: to be able, cannot choose but, cannot but, had better, would rather, would sooner:

e. g. You would better let your heart be without words, than your words without heart. (Anonymous).

Everybody is able to forget but to forgive.

6. As a part of a compound verbal aspect (aspective) predicate the infinitive follows:

a). Verbs denoting the beginning of the action: to begin, to commence, to start.

E.g. She began to cry and cried until Tommy agreed to have her with him.

b). Verbs denoting duration of the action: to continue to go on.

e. g. So, after some rest we continued to move towards the town.

c). Verbs denoting the end of the action: to cease, to complete, to end, to finish, but to stop.

e. g. How’s Tom?–– I do not know. All I know about him is that he finished to study at school.

But They stopped to talk. (here the infinitive expresses the function of an adverbial modifier of purpose).

7. As a direct object:

a). When used in this function the infinitive may be placed after verbs requiring two objects: to advise, to allow, to ask, to beg, to force, to help, to inspire, to implore, to instruct, to invite, to order, to persuade, to press, to prompt, to recommend, to remind, to request, to tell, to teach, to trust, to train, to warn.

e. g. She reminded me to lock the door.

I trust them to solve the problem.

I encouraged her to tell everything.

b). May follow directly the verb: to afford, to agree, to aim, to arrange, to ask, to attempt, to beg, to care, to claim, to decide, to demand, to deserve, to desire, to fight, to forget, to grow, to help, to hesitate, to learn, to offer, to plan, to prepare, to pretend, to promise, to refuse, to resolve, to scorn (= to refuse), to seek, to struggle, to survive (= to live), to swear, to threaten, to vow, to wait.

e. g. He refused me to help in solving the problem.

c). Sometimes the infinitive in the function of the direct object may be introduced by the following words: who, what, which, why, when, where, how.

e. g. He (Man) learned how to use the stone instruments, how to use fire, how to build and how to bring up children. And that was the beginning of civilisation.

Note 1: Special attention should be paid to the verbs to allow, to order, to permit. Structures like ‘It allows to make the following conclusions’ are incorrect. If there is no notional object, a formal one should be used: