Section 16.1 Nonfinite Verb Forms
Consider these three phrases: to write, writing, written. You have used all three countless times, in sentences like She loves to write, Writing is her passion, and a well-written essay. But what kind of verb forms are these? They do not carry tense. They do not agree with a subject. They cannot stand alone as the main verb of a sentence. They are nonfinite—and understanding why that label matters will sharpen your ability to analyze any sentence you encounter.
Verbs can be finite or nonfinite. Finite verbs are marked for tense and agree with their subjects. Nonfinite verbs lack tense marking and cannot serve as the main verb of an independent clause.
Three Types of Nonfinite Forms.
The three nonfinite forms—infinitive, gerund/present participle, and past participle—differ in shape and function. The table below summarizes them; the subsections that follow explain how each one works.
| Form | Example | Characteristics |
|---|---|---|
| Infinitive | (to) write | Base form, with or without to |
| Gerund/Present Participle | writing | -ing form |
| Past Participle | written | -ed or irregular form |
Infinitives.
To-infinitive: to + base verb
-
She wants to leave.
-
It’s important to practice.
Bare infinitive: base verb without to
-
She can leave. (after modals)
-
Let him go. (after let, make, have)
-
I saw her leave. (after perception verbs)
Gerunds and Present Participles.
The -ing form serves two functions:
Gerund (nominal function):
-
Swimming is fun. (subject)
-
She enjoys reading. (object)
Present participle (adjectival/adverbial function):
-
the running water (adjectival)
-
Knowing the answer, she raised her hand. (adverbial)
Progressive auxiliary:
-
She is writing. (part of verb phrase)
Past Participles.
The past participle (-ed or irregular) serves several functions:
Perfect auxiliary:
-
She has written a book.
Passive auxiliary:
-
The book was written by her.
Adjectival:
-
the broken window
-
a book written by Hemingway
The Perfect Participle.
There is one additional participial form worth noting: the perfect participle, formed with having + past participle. It signals that one action was completed before another:
-
Having finished the exam, she left the room.
-
Having read the report, the committee made its decision.
The perfect participle functions like a present participle (it can modify a noun phrase or provide circumstantial information), but it adds the meaning of completed prior action. You will see this form in exercises throughout the rest of the book.
