Done

-Present perfect:
1. We use the Present Perfect Tense to talk about experiences. It is important if we have done it in our lives or not. It is not important when we did it.
Examples 
   I havebeen abroad two times. 
   Anna has never broken a leg. 
   Have you ever eaten sushi?
Tip! We often use never and ever with the Present Perfect Tense to talk about experience.
2. We use thePresent Perfect Tense to talk about an action which started in the past and continuous up to now.
Examples 
   I have been a teacher for more than ten years. 
   We haven't seen Janine since Friday.    How long have you been at this school?
Tip! We often use since and for to say how long the action has lasted.
3. We also use the Present Perfect Tense to talk about a past action that hasthe result in the present.
Tip! We often use just, already and yet with the Present Perfect Tense for an action in the past with the result in the present.
FORM: We make the Present Perfect tense withthe correct form of the auxiliary verb have(have/has) and the third form (past participle) of the mail verb.
To form the past participle of the regular verbs, we add ed to the infinitive.
 -Past Perfect:
The past perfect is used to show you which of two events happened first. Imagine that two things happened in the past:
 
I went to see the movie. |
We discussed the movie in class. |Here, we don't know which order the events happened in. That may be important -- perhaps I went to see the movie after the discussion, or maybe I saw the movie before the discussion. There are manyways to make this sequence clear, and the past perfect is one of them. This is how we do it:
 
I went to see the movie. We had discussed it in class. |
Here, we KNOW that the discussion took placeFIRST -- even though the sentence describing it comes afterwards. We discussed the movie, and THEN I went to see it. This can be very useful when you are telling a story or relating a sequence of...