Present Perfect

•  Present Perfect

We use the Present Perfect to say that an action happened at an unspecified time before now. The exact time is not important.

• Just: a short time ago
• Already: before you expected.
• yet: until now (negatives).

 Examples:

You have seen that movie many times.
Have you seen that movie many times?
You have not seen that movie many times.

• Present Perfect  Progressive

Describes an action that began in the past, continues in the present, and may continue in the future.

Examples:
 You have been waiting here for two hours.
Have you been waiting here for two hours?
You have not been waiting here for two hours

• Present Perfect Simple

The present perfect simple expresses an action that is still going on or that stopped recently, but has an influence on the present. It puts emphasis on the result.

 Examples:

Have you finished the job? No, I haven't finished yet. Yes, I have already finished. She's just finished her job.