The Present Perfect

Let's study this example:
-Edward is looking for his pen. He can't find it.
-He has lost his pen.
-(He has lost his pen) means he has lost it recently, and he still doesn't have it.

The present perfect is the use of:
have/has + the past participle.

-I have finished
- we have been
- he has eaten
-It has played
etc.

# have is shortened ('ve) = I've, we've, they've, you've.
# has is shortened ('s) He's =he has.
Ex; It's been a pleasure = it has been a pleasure.

When we say 'something has happened', this is usually new information:
- Ow! I've cut my finger
- The road is closed. There has been an accident.
- (On the news) Police have arrested the criminal.

When we use the present perfect, there is a connection with now. The action in the past has a result now:
-A:'Where's your hat?'     B:'I don't know. I've lost it',
(= I don't have it now).
-He told me his name, but I've forgotten it.
 (= I can't remember it now)
-A:'Is Susan here?'    B:'No, she's gone out',
(=she is out now)
- I can't find my bag. Have you seen out?
(= Do you know where it is now?)

You can use the present perfect with just, already & yet.
Just = a short time ago:
     - A:'Are you hungry?'     B:'No, I've just had lunch'.
     -Hello. Have you just arrived?
Already is used to say something happened earlier than expected:
     -A:'Don't forget to do your homework.'             B:'I've already done it.'
-A:' What time will your uncle arrive?'
B:' He's already arrived?'
Yet  = until now. Yet is used when we expect something to happen.
- Is dinner ready yet?
-Has your uncle arrived yet?