Infinitives can be used after certain verbs including agree, ask, decide, help, plan, hope, learn, want, would like, and promise.

Where do we use infinitive?

The to infinitive can be used to express purpose or necessity after a verb followed by a pronoun or a noun. purpose: I brought it to read on the train = so that I could read it. necessity: There is work to do! = work that must be done.

How do you use infinitive in a sentence?

You can form an infinitive verb by adding "to" in front of any base verb. Infinitive verbs are not conjugated like other verbs; they stay in their infinitive forms in a sentence. Examples of common infinitive verbs include: to be (I want to be an astronaut.)