How is the present perfect tense formed?

Answer 1

TO HAVE in the Present Tense plus the main verb in the Past Participle (the 3rd form).

It expresses actions that:

1. began in the past and are still going on today:

I have been studying the piano for 19 months.

2. began and ended in the past, but the respective action still has obvious results/effects in the present:

She has learnt the lesson (and she knows it).

We have told Jerry the truth (and he knows it).

I've seen this film (I don't want to see it once more).

3. took place in the past, but VERY RECENTLY:

I'm so tired, I have just returned from the supermarket.

4. with words like: ALREADY, OFTEN, EVER, LATELY, USUALLY, NEVER, RECENTLY, etc.

5. took place in the past at AN UNSPECIFIED MOMENT:

I've met Susie. He has broken his left foot. Have you read it?

Answer 2

The present perfect tense is formed by using the auxiliary verb "have" (or "has" for third person singular subjects) followed by the past participle of the main verb. For example, "I have finished my homework."