Infinitive with and without to

FORM
She made us wait for half an hour.
John lets the dog sleep on the sofa.
The infinitive of a verb has two forms: the to-infinitive and the infinitive without to.
The to-form consists of to plus the base form of the verb:
I want to speak to you.
We came here to work, not to play.
The form without to consists of the base form of the verb:

TO-INFINITIVE
We use the to-infinitive after a number of common main verbs.
For example:

agree
demand
long
pretend
aim
fail
love
promise
arrange
forget
manage
propose
ask
hate
mean
refuse
begin
help
need
remember
choose
hope
offer
try
claim
intend
plan
want
continue
learn
prefer
wish
decide
like
prepare
TO-INFINITIVE

TO-INFINITIVE
We arranged to see the bank manager and applied for a loan.
Mrs Harding asked us to call in on our way home.
Did you remember to post the letter to your mother?
He just wants everyone to be happy.
Tip:Some of these verbs are also often followed by -ing.

TO-INFINITIVE
To work in a developing country had always been her ambition.
To get there before lunch, you would have to take the seven o’clock train.
We can use the to-infinitive in a clause with a verb that has no subject (a non-finite clause). The to-infinitive focuses on the idea of an action or the results of an action, rather than the action in itself:

INFINITIVE WITHOUT TO
She can sleep in the guest room tonight.
Will you need to rent a car during your stay?
He lets us use some of his land to grow vegetables.
You can’t make a cat do anything it doesn’t want to do.
I just want to help you (to) understand the situation better.
We also use the infinitive without to after let, make and (optionally) help:
We use the infinitive without to after modal verbs can, could, may, might, will, shall, would, should, must: