1) Finite verb phrases show contrast in the meaning expressed by the verb. For example, they show contrast in:
a) Tense - He plays football. / He played football.
b) Number and Person - He plays. / They play. / I am. / You are.
c) Allow the expression of facts, possibilities, wishes, and other contrasts of mood - He asked the car to be moved. / It was moved.
2) If there is a series of verbs in the verb phrase, the finite verb is always the first. For example:
I was being paid. / They have been asked.
3) Nonfinite forms do not express contrasts of tense, number, person, or mood. They stay the same in clause regardless of any grammatical variation which may be taking place alongside them. There are three nonfinite forms in the verb:
a) The -ing participle - I'm going. / They're going. / He was going. / Going home, I/we/they felt concerned.
b) The -ed participle - I've asked. / He was asked. / They were asked. / Asked to come early, I/you/we arrived at 3.
c) The base form used as an infinitive - They might see. / I'll see. / He wants to see.