THE INFINITIVE

FUNCTION

The most common uses of the infinitive are:

To indicate the purpose or intention of an action (where the 'to' has the same meaning as'in order to' or 'so as to'):

• She's gone to collect her pay cheque.
• The three bears went into the forest to find firewood.

As the subject of the sentence:

• To be or not to be, that is the question.
• To know her is to love her.
  (Note: this is more common in written English than spoken)

With nouns or pronouns, to indicate what something can be used for, or what is to be done with it:

• Would you like something to drink?
• I haven't anything to wear.
• The children need a garden to play in.

After adjectives in these patterns:

• It is + adjective +to-infinitiveIt is good to talk
• It is + adjective + infinitive + for someone + to-infinitive.It is hard for elephants to see mice
• It is + adjective + infintive + of someone + to-infinitive.
  It is unkind of her to say that.

After an adjective + noun when a comment or judgement is being made:

• It was a stupid place to park the car.
• This is the right thing to do.
• It was an astonishing way to behave.

With too and enough in these patterns:

too much/many (+ noun) + to-infinitive

• There's too much sugar to put in this bowl.
• I had too many books to carry.

too + adjective + to-infinitive

• This soup is too hot to eat.
• She was too tired to work.

too + adverb + to-infinitive

• He arrived too late to see the actors.

enough (+ noun) + to-infinitive

• I've had enough (food) to eat.

adjective + enough + to-infinitive

• She's old enough to make up her own mind.

not enough (+noun) + to-infinitive

• There isn't enough snow to ski on.

not + adjective + enough + to-infinitive

• You're not old enough to have grand-children!

THE INFINITIVE

OTHER FORMS

The infinitive can have the following forms:

• The perfect infinitive
• The continuous infinitive
• The perfect continuous infinitive
• The passive infinitive

NOTE: as with the present infinitive, there are situations where the to is omitted, e.g. after most modal auxiliaries.

The perfect infinitive:

to have + past participle , e.g. to have broken, to have seen, to have saved. This form is most commonly found in Type 3 conditional sentences, using the conditional perfect, e.g. If I had known you were coming I would have baked a cake. Examples Someone must have broken the window and climbed in. I would like to have seen the Taj Mahal when I was in India. He pretended to have seen the film. If I'd seen the ball I would have caught it.

The continuous infinitive:

to be + present participle, e.g.to be swimming, to be joking, to be waiting Examples I'd really like to be swimming in a nice cool pool right now. You must be joking! I happened to be waiting for the bus when the accident happened.

The perfect continuous infinitive:

to have been + present participle Examples to have been crying to have been waiting to have been painting  The woman seemed to have been crying. You must have been waiting for hours! He pretended to have been painting all day.

The passive infinitive:

to be + past participle, e.g. to be given, to be shut, to be opened Examples I am expecting to be given a pay-rise next month. These doors should be shut. This window ought to be opened.

THE INFINITIVE

VERBS NORMALLY FOLLOWED BY THE INFINITIVE

A. The to-infinitive is used after the verbs in this group, without a preceding noun. The verbs marked * can also be followed by a 'that-clause'

Examples

VERB	TO-INFINITIVE
I hope...	to see you next week.
	THAT- CLAUSE
I hope...	that I'll see you next week

List of verbs normally followed by the infinitive

afford agree1 aim appear1 arrange1 bother care claim1 condescend consent decide1 demand1 determine1 endeavour

fail guarantee1 happen 1 hasten have (= be obliged) hesitate hope1 learn long manage offer prepare pretend1 proceed

promise1 propose prove (= turn out) refuse resolve1 seek seem1 strive swear1 tend threaten1 trouble undertake volunteer vow1

¹ These verbs can only be followed by a 'that-clause' when they have the subject 'it'. 

Example

• It appeared that no-one had locked the door.

Examples

• He claimed to be an expert.
• I managed to reach the top of the hill.
• I know you're only pretending to love me!
• Don't pretend that you know the answer.
• She failed to explain the problem clearly.
• The customs man demanded to search our luggage.
• I can't afford to go out tonight.

THE INFINITIVE

NEGATIVE INFINITIVE

To form the negative infinitive, place not before the to- or zero infinitive:e.g. not to worry:

It's hard not to worry about exams.

Examples

• I decided not to go to London.
• He asked me not to be late.
• Elephants ought not to marry mice.
• You'd better not smile at the crocodile.
• I'd rather not eat meat.

THE INFINITIVE

INFINITIVE AFTER QUESTION WORDS

These verbs: ask, decide, explain, forget, know, show, tell, understand, can be followed by a question word such as where, how, what, who, when or 'whether' + the 'to-infinitive'.

Examples

• She asked me how to use the washing machine.
• Do you understand what to do?
• Tell me when to press the button.
• I've forgotten where to put this little screw.
• I can't decide whether to wear the red dress or the black one.

The question word Why is followed by the zero infinitive in suggestions:

Examples

• Why wait until tomorrow?
• Why not ask him now?
• Why walk when we can go in the car?
• Why not buy a new bed for your bedroom?
• Why leave before the end of the game?
• Why not spend a week in Beirut and a week in Baghdad?