Infinitive Phrase
Identify the infinitive head first, then include the words that complete or modify it. Do not assume every “to + word” sequence is an infinitive: “to” can also be a preposition, and English also has bare infinitives without “to.”
An infinitive phrase is built around an infinitive—usually “to” plus the base form of a verb—together with its complements or modifiers. The phrase can function in noun-like, adjective-like, or adverb-like ways depending on the sentence.
Key details
Important caveats
Boundary
Distinguish infinitival “to” from prepositional “to.” In “look forward to meeting,” “to” is a preposition and “meeting” is not an infinitive.
Further guidance
Function
Check the phrase’s role in the larger sentence: it may behave like a noun (“To leave now would help”), modify a noun (“a chance to improve”), or express purpose/result (“She called to confirm”).
Identify
Locate the base-form verb introduced by infinitival “to,” then include objects, complements, and modifiers that belong with that verb.
Worked Example
In “We stayed late to finish the report,” “to finish the report” is an infinitive phrase expressing purpose; “the report” is the object of “finish.”
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Gerunds (opens in a new tab)Purdue Online Writing Lab · Purdue defines a gerund phrase as a gerund plus modifiers, objects, or complements and demonstrates noun-like functions including subject, object, complement, and object of a preposition.
- Commas After Introductions (opens in a new tab)Purdue Online Writing Lab · Purdue identifies introductory dependent clauses introduced by words such as after, although, because, if, since, until, and when and explains their relation to the main independent clause.