You can also use multiple infinitives in a single sentence: “Today, I plan to run three miles, to clean my room, and to update my budget.” All three of these infinitives follow the verb plan. Other verbs that often come before infinitives include want, convince, try, able, and like.
As a Noun Phrase
The infinitive can also be used to express an action in an abstract, general way: “To err is human”; “To know me is to love me.” No one in particular is completing these actions. In these sentences, the infinitives act as the subjects.

Infinitives can also serve as the object of a sentence. One common construction involves a dummy subject (it): “It was nice to meet you.”
As a Modifier
Infinitives can be used as an adjective (e.g., “A request to see someone” or “The man to save us”) or as an adverb (e.g., “Keen to get on,” “Nice to listen to,” or “In order to win“).
In Questions
Infinitives can be used in elliptical questions as well, as in “I don’t know where to go.”

Note: The infinitive is also the usual dictionary form or citation form of a verb. The form listed in dictionaries is the bare infinitive, although the to-infinitive is often used in referring to verbs or in defining other verbs: “The word amble means ‘to walk slowly'”; “How do we conjugate the verb to go?”

Certain helping verbs do not have infinitives, such will, can, and may.

Split Infinitives?
One of the biggest controversies among grammarians and style writers has been the appropriateness of separating the two words of the to-infinitive as in “to boldly go.” Despite what a lot of people have declared over the years, there is absolutely nothing wrong with this construction. It is 100 percent grammatically sound.

Part of the reason so many authorities have been against this construction is likely the fact that in languages such as Latin, the infinitive is a single word, and cannot be split. However, in English the infinitive (or at least the to-infinitive) is two words, and a split infinitive is a perfectly natural construction.

Try to versus Try and
One common error people make is saying try and instead of try to, as in “I’ll try and be there by 10:00 tomorrow.” However, try requires a to-infinitive after it, so using and is incorrect. While this construction is acceptable in casual conversation, it is not grammatically correct and should not be used in formal situations.

Practice
Identify the infinitives in the following sentences:
Paulina is the girl to beat.
It was really nice to hear from you again.
It looks like Dash wants to fail.

The Bare Infinitive
As we mentioned previously, the infinitive can sometimes occur without the word to. The form without to is called the bare infinitive (the form with to is called the to-infinitive). In the following sentences both sit and to sit would each be considered an infinitive:
I want to sit on the other chair.
I can sit here all day.

Infinitives have a variety of uses in English. Certain contexts call for the to-infinitive form, and certain contexts call for the bare infinitive; they are not normally interchangeable, except in occasional instances like after the verb help, where either can be used.

As we mentioned earlier, some verbs require the bare infinitive instead of the to-infinitive:
The helping verb do
Does she dance?
Zi doesn’t sing.

Helping verbs that express tense, possibility, or ability like will, can, could, should, would, and might
The bears will eat you if they catch you.
Lucas and Gerardo might go to the dance.
You should give it a try.

Verbs of perception, permission, or causation, such as see, watch, hear, make, let, and have (after a direct object)
Look at Caroline go!
You can’t make me talk.
It’s so hard to let someone else finish my work.

The bare infinitive can be used as the object in such sentences like “What you should do is make a list.” It can also be used after the word why to ask a question: “Why reveal it?”

The bare infinitive can be tricky, because it often looks exactly like the present tense of a verb. Look at the following sentences for an example:
You lose things so often.
You can lose things at the drop of a hat.

In both of these sentences, we have the word lose, but in the first sentence it’s a present tense verb, while in the second it’s a bare infinitive. So how can you tell which is which? The easiest way is to try changing the subject of the sentence and seeing if the verb should change:
She loses things so often.
She can lose things at the drop of a hat.

Practice
Identify the infinitives in the following sentences:
What you should do is stop talking for a moment and listen.
Oh, that must be Lebo at the door.
Why walk when I could run?