Infinitive phrase
An infinitive phrase begins with to and is followed by the base form of the verb. For most verbs their base form is similar to the one used after words like I, You, They, We. There are some irregular verbs that do not have the same base form as their conjugated forms. "To be" is one of these verbs. The infinitive "to be" conjugates to become am, is, or are after the subject. Infinitive phrases often act as a noun, adjective, or adverb instead of as a verb.