PRESENT PERFECT

                   

Mary is looking for her key. 

                     She can`t find it. She has lost his key                        

                               

Pronouns	Auxiliary	Verb in Past Participle
I	have	worked
You	have	studied
He	has	done
She	has	written
We /  You  /  They	have	been

The present perfect simple is HAVE /  HAS  +  PAST PARTICIPLE. The past participle often ends in -ED  (finished /  decided  / lived etc), but many important verbs are irregular (lost / been / written etc).

When we use the present perfect there is always a connection with now. The action in the past has a reuslt now:

He told me his name but I have forgotten it. (I can`t remember it now)

Is Sally here? No, she is gone out (she is out now).

We often use the present perfect to give new information or to announce a recent happening:

The police have arrested two men.

You can use the present perfect with JUST,    ALREADY, and YET

JUST= a short time ago

Would you like something to eat?  " No, thanks, I have just had lunch"

We use ALREADY to say that something happened sooner than expected

What time is Mark leaving?  He`s already gone

YET=   "until now" and shows that the speaker is expecting something to happen. Use YET only in questions and negative sentences.

I have written the letter but I haven`t posted it yet.