We use the to-infinitive:

• to express purpose (to answer "Why...?"):

He bought some flowers to give to his wife.
He locked the door to keep everyone out.

We sometimes say in order to or in order not to:

We set off early in order to avoid the traffic.
They spoke quietly in order not to wake the children

… or we can say so as to or so as not to:

We set off early so as to avoid the traffic.
They spoke quietly so as not to wake the children.

• after certain verbs (see verbs followed by infinitive), particularly verbs of thinking and feeling:

choose, decide, expect, forget, hate, hope, intend, learn, like,
love, mean, plan, prefer, remember, want, would like, would love

… and verbs of saying:

agree, promise, refuse

They decided to start a business together.
Remember to turn the lights out.

Some verbs are followed by a direct object and the infinitive(see verbs followed by infinitive):

advise, ask, encourage, invite, order, persuade, remind, tell, warn,
expect, intend, would prefer, want, would like

She reminded me to turn the lights out.
He encouraged his friends to vote for him.

• after certain adjectives.

Sometimes the to-infinitive gives a reason for the adjective:

  • disappointed
  • glad
  • sad
  • happy
  • anxious
  • pleased
  • surprised
  • proud
  • unhappy

We were happy to come to the end of our journey
= We were happy because we had come to the end of our journey
John was surprised to see me
= He was surprised because he saw me

Other adjectives with the to-infinitive are:

  • able
  • unable
  • due
  • eager
  • keen
  • likely
  • unlikely
  • ready
  • prepared
  • unwilling
  • willing

Unfortunately I was unable to work for over a week.
I am really tired. I’m ready to go to bed.

We often use the to-infinitive with these adjectives after it to give opinions:

  • difficult
  • easy
  • possible
  • impossible
  • hard
  • right
  • wrong
  • kind
  • nice
  • clever
  • silly
  • foolish

It’s easy to play the piano, but it’s very difficult to play well.
He spoke so quickly it was impossible to understand him.

We use the preposition for to show who these adjectives refer to:

  • difficult
  • easy
  • possible
  • impossible
  • hard

It was difficult for us to hear what she was saying.
It is easy for you to criticise other people.

We use the preposition of with other adjectives:

It’s kind of you to help.
It would be silly of him to spend all his money.

• As a postmodifier (see noun phrases) after abstract nouns like:

  • ability
  • desire
  • need
  • wish
  • attempt
  • failure
  • opportunity
  • chance
  • intention

I have no desire to be rich.
They gave him an opportunity to escape.
She was annoyed by her failure to answer the question correctly.

• We often use a to-infinitive as a postmodifier after an indefinite pronoun (See indefinite pronouns):

When I am travelling I always take something to read.
I was all alone. I had no one to talk to.
There is hardly anything to do in most of these small towns.


 

Exercise

Section: 

Comments

Hi, I am an English teacher and one of my students has stumped me with this question... Why is the word "to" used after the verb and before the pronoun in sentences 1, and not in sentences 2?

1. Let me explain to you something.
2. Let me make you a cake.

Thanks!

Hi caseyw,

These sentences have direct ('something' and 'a cake', respectively) and indirect objects ('you'). Some verbs require the indirect object to be in a prepositional phrase (generally with 'to' or 'for') and 'explain' is one of these verbs. 'Make' can also have a similar construction if you put the indirect object at the end:

Let me make a cake for you.

 

Best wishes,

Peter

The LearnEnglish Team

hello, could somebody explain me about the structure and the sense of this sentences?
-She is to study marketing and management.
-He is to marry Susan.

Hello manuel24,

The structure here is [be to + verb]. It is a way of talking about the future and is generally used to talk about things which a person is supposed to or scheduled to do. It has a similar meaning to 'supposed to' or 'meant to'.

 

Best wishes,

Peter

The LearnEnglish Team

hello
To is infinitive verb marker.. but in this "You can keep it" KEEP is not finite by subject YOU.
but i never heard that anyone says "you can to keep it". could you explain sir what happens in that sentences.

Hello Tharanga pud,

Infinitives are sometimes used with 'to' and sometimes without 'to'; when they are used without 'to' (such as in 'You can keep it'), they are often referred to as a 'bare infinitive' or 'base form'. Verbs that come after modal verbs like 'can' are used in the base form. This is why 'You can keep' is correct and 'You can to keep' is not.

All the best,
Kirk
The LearnEnglish Team

thank you!

Hello.would you tell me when we use simple form after "help"?and when we use to+infinitive?
with best wishes.

Hello rastak keen,

Both forms are fine and mean the same thing; they are alternatives.

I helped him to get into the car.

I helped him get into the car.

 

Best wishes,

Peter

The LearnEnglish Team

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