• Verbs— words that belong the verb word class — have five syntactic forms: the base form, the -s form, the -ing participle, the past form and the -ed participle (often called the “past participle”).The -s form and the past form are finite. The -ing participle and the past participle are non-finite. The base form is sometimes finite and sometimes non-finite.
• A verb phrase containing just one word is finite if that word is a finite verb and non-finite if that word is a non-finite verb. Verb phrases containing more than one word are finite if their first word is a finite verb and non-finite if their first word is a non-finite verb.
When the base form is the first word in a verb phrase — i.e. when it occupies the position that determines whether the phrase is finite or non-finite — it is finite. It appears in its non-finite form when it is preceded by an auxiliary (in a finite phrase.) (For example, “Harry does not love Jill.”)
• A clause is finite if its verb phrase is finite and non-finite if its verb phrase is non-finite. (The clause that constitutes a simple sentence always has a finite verb phrase; the main clause of a complex sentence always has a finite verb phrase; all the independent clauses of a compound sentence always have finite verb phrases.)
• some examples:
Dick lives with Jane.
While going to university, Dick had been living with Jane.
Dick found a job for Jane in Harry’s company.
Dick and Jane work for Harry.
Harry had always wanted to raise a big family.
Raising a big family had always been Harry’s dream.
Although raised on a farm, Harry had no interest in animals.
Harry was proud to have served in the army.
• note the following: (i) the verb phrases in the four finite clauses — lives, had been living, found, and work — all begin with a finite verb; (ii) in each of these cases “tense contrast” is possible — i.e. the first and fourth examples could be put into the past tense, and the second and third could be put into the present; (iii) in the first and fourth examples, singular/plural contrast is possible, i.e. in the first example if a plural subject such as Tom and Dick were substituted there would be a resulting change in the verb (from lives to live) and likewise if, in the fourth example a singular subject such as Dick were substituted there would be a comparable change in the verb (from work to works); (iv) in the case of the four examples of non-finite clauses, typically, no tense or “number” contrasts are possible; (v) for the special case of finite verb phrases that begin with a modal auxiliary see the notes and reference page; (vii) for a comment on the importance of the finite/non-finite distinction to ESL instruction see About Error Sheets, page 5.