Present Perfect - Hiện tại Hoàn thành

FORM of Present Perfect
The Present Perfect has two parts: The verb to have and the Past Participle (PP) of
the main verb (have/has + PP). See examples below.
S + have/has + PP
I have learnt English.
He has swum well.
They have watched TV.
S + have/has not+ PP
I haven't learnt English.
He hasn't swum well.
They have not watched TV.
Have/Has + S + PP?
Have you learnt English?
Has he swum well?
Have they watched TV?

The Present Perfect refers to an action happened in the past but it is still related to
the present. The time of the action is before now but not specified, and we are
often more interested in the result than in the action itself.

USEs of Present Perfect
1. to describe an action or situation that started in the past and continues in
the present
 I have lived in New York for nine years.
 We have been here since Friday.
 He has played football since he was a child.
2. to describe an action performed during a period that has not yet finished:
 James has not finished his homework yet.
 Susan hasn't mastered Japanese, but she can communicate.

 He has never traveled by train.
 Joan has studied two foreign languages.
 A: Have you ever met him?
B: No, I have not met him.

Forms of Negatives and Questions
Negative sentences and questions are formed with the auxiliary verb 'have'.
The 3rd person singular of 'have' is 'has. This means that in negative sentences and
questions, we have to use 'has'.
 He has never been to America.
 Has Thomas finished his writing task yet?

Signal Words of Present Perfect:
already, ever, just, never, not yet, so far, till now, up to now, since, for