What is a non-finite verb?
A non- finite verb is a form of a verb that does not have a subject and and does not exhibit tense and number in an independent clause or sentence. In English, the non-finite verb forms are infinitives andgerunds and participles. Non-finite verbs are distinguished from finite verbs which show a distinction in tense and number, and may stand alone as the main verb in an independent clause.
They are writing the letter. - They is a subject; are is a finite; writing is a non-finite verb (which does not exhibit tense nor number); the match is an object.
They wrote the letter . - They is a subject; wrote is a finite verb; the letter is an object.
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