Sentence

Explanation

I want to go to school.

Infinitive as object of the verb.

To understand English is my goal.

It is my goal to understand English.

Infinitive as subject of the clause.

The infinitive can be replaced by "it" as the subject of a sentence, with the infinitive placed after the verb.

These two sentences have the same meaning, but the second is more common than the first.

I went to Canada to study English.

I went to Canada in order to study English.

Infinitive used to show purpose, which means it answers the question: why?

"In order to" also expresses purpose, so these two sentences have the same meaning.

I am happy to tell you my name.

Use an infinitive after certain adjectives — usually these adjectives describe how a person feels, for example: glad, sorry, ready, lucky, afraid, sad, pleased.

(Most dictionaries will indicate if an adjective is followed by an infinitive.)

I expect to pass my test tomorrow.

NOT: I expect passing my test tomorrow.

There are many verbs that use infinitives as an object of the verb. "Expect", for example, must be followed by an infinitive. A gerund cannot follow "expect".

(Most dictionaries will indicate if a verb is followed by a gerund or an infinitive.)

I tell Max to go to bed every night at 9:00.

Some verbs are followed by a noun or pronoun and then an infinitive.

Max is too young to stay up until 10:00 p.m. He must go to bed now.

Cam is old enough to stay up until 10:00 p.m. He can go to bed at 10:00 p.m.

Use an infinitive with "too" and "enough".

"Too" adds a negative meaning to the adjective. This sentence means that Max is very young. He should go to bed before 10:00 p.m. "Too" usually goes before the adjective.

"Enough" adds a positive meaning to the adjective. It usually goes after the adjective.

Tom sees Mary run down the street three times a week.

OR

Tom sees Mary running down the street three times a week.

Tom makes Mary stop.

Tom lets Mary borrow his car when he does not need it.

Use the simple form, or a gerund, after a verb of perception, such as: see, hear, feel.

Use the simple form after a causative verb, such as: make, have, let.

Use the simple form after "let".

Tom told Mary not to run.

Place the negative "not" before the infinitive.