THE INFINITIVE

1. Form

The infinitive is the base form of a verb. It may be preceded by 'to' (the to-infinitive) or
stand alone (the base or zero infinitive).

2. Infinitive with or without 'to'

The to-infinitive is used:

• after certain verbs. e.g. want, wish, agree, fail, mean, decide, learn
• after the auxiliaries to be to, to have to, and ought to
• in the pattern 'it is + adjective + to-infinitive'

Examples

with 'to'

• The elephant decided to marry the mouse

• The mouse agreed to marry the elephant
• You will have to ask her
• You are to leave immediately
• He ought to relax
• She has to go to Berlin next week
• It's easy to speak English
• It is hard to change jobs after twenty years
• It's stupid to believe everything you hear

without 'to'

• I would rather visit Rome.

• She would rather live in Italy.
• Would you rather eat steak or fish?
• He would rather work in a bank.
• I'd rather be a forest than a tree.

THE ZERO INFINITIVE

The zero infinitive is used:

1. after most auxiliaries (e.g. must, can, should, may, might)

 2. after verbs of perception, (e.g. see, hear, feel) with the pattern verb + object +
zero infinitive
3. after the verbs 'make' and 'let', with the pattern make/let + object + zero infinitive
4. after the expression 'had better'
5. after the expression 'would rather' when referring to the speaker's own actions

Examples:

After auxiliaries:
• She can't speak to you.
• He should give her some money.
• Shall I talk to him?
• Would you like a cup of coffee?
• I might stay another night in the hotel.
• They must leave before 10.00 a.m.

After verbs of perception:

• He saw her fall from the cliff.
• We heard them close the door.
• They saw us walk toward the lake.
• She felt the spider crawl up her leg.

After the verbs 'make' and 'let':

• Her parents let her stay out late.
• Let's go to the cinema tonight.
• You made me love you.
• Don't make me study that boring grammar book!

NOTICE that the 'to-infinitive' is used when 'make' is in the passive voice:

• I am made to sweep the floor every day.

• She was made to eat fish even though she hated it.

After 'had better':

• We had better take some warm clothing.
• She had better ask him not to come.
 • You'd better not smile at a crocodile!
• We had better reserve a room in the hotel.
• You'd better give me your address.
• They had better work harder on their grammar!

After 'would rather':

Note: this is ONLY when referring to the speaker's own actions - see 'would rather' in
section on Unreal past.

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.

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?

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-infinitive
It 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!

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.

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'

Example:

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 fail promise1

AGREE1 guarantee1 propose
aim happen 1 prove (= turn out)
appear1 hasten refuse resolve1
arrange1 have (= be obliged) seek
bother hesitate seem1
care hope1 strive
claim1 learn swear1
condescend long tend
consent manage threaten1
decide1 offer trouble
demand1 prepare undertake
determine1 pretend1 volunteer
endeavour proceed 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
VERBS NORMALLY FOLLOWED BY THE INFINITIVE

B. These are the most common of the verbs that are normally followed by a noun +
infinitive. The verbs marked * may also be followed by a 'that-clause'.

Example

VERB NOUN INFINITIVE

He reminded me to buy some eggs.
THAT-CLAUSE
He reminded me that I had to buy some eggs.

ACCUSTOM entitle order*

AID entreat persuade*
APPOINT force press
ASSIST get prompt
CAUSE implore* provoke
CHALLENGE incite remind*
COMMAND* induce require*
defy inspire stimulate
direct* instruct* summon
drive invite teach
empower lead tell
enable leave (make someone responsible) tempt
encourage oblige trust*
entice warn*

Notes:

* command, direct, entreat, implore, order, require, trust:

there is no noun between these verbs and a 'that-clause':

• The general commanded his men to surrender.

• The general commanded that his men should surrender.

persuade and remind:

there is always a noun between these verbs and a 'that-clause':

• You can't persuade people to buy small cars.

• You can't persuade people that small cars are better.

instruct, teach, warn:

the noun is optional between these verbs and a 'that-clause':

• She taught her students to appreciate poetry.

 • She taught her students that poetry was valuable.
• She taught that poetry was valuable.

Examples

• The professor challenged his students to argue with his theory.

• This law empowers the government to charge more taxes.
• You can't force me to do something I don't agree with.
• You are obliged to drive on the left in England.
• I invited the new student to have dinner with me.
• What inspired you to write this poem?
• The elephant told the mouse to climb up his tail.

VERBS NORMALLY FOLLOWED BY THE INFINITIVE

C. These are the most common of the verbs followed by a to-infinitive, with
or without a noun.

Example
• I asked him to show me the book.
• I asked to see the book.

ASK* expect*
beg* help
choose mean* (=intend)
dare request*
desire* want
elect wish*

The verbs marked * can also be followed by a that-clause

Note:

dare: In negative and interrogative sentences the infinitive with or without 'to' is possible,
though it is more common to omit the 'to':

• I never dared tell him what happened.

• Dare you tell him the news?
• Would you dare (to) jump out of a plane?

Examples

We've chosen John to represent the company at the conference.

• The driver didn't try to stop after the accident.
• We expect you to do your best in the exam.
• Do you want to go to the beach?
• Do you want me to go with you to the beach?
• You are requested to be quiet in this library.