Urgent: Please Help !

[wEEzEr]

I was wondering if someone could help me with this.
Explain me the use of for, since, already and yet in the present perfect!!
please...it's a matter of life or death!!

[Rusty]

I was wondering if someone could help me with this.
Explain me the use of for, since, already and yet in the present perfect!!
please...it's a matter of life or death!!
He has lived here for ten years. For = a duration of time, a number of years, etc.
He has lived here since 2001. Since establishes the beginning time.
He has already purchased his ticket/He has purchased his ticket already. Already = before now.
He has not purchased his ticket yet/He has not yet purchased his ticket. Not yet + present perfect = At any time in the past, up to the present.

This may be over-simplified. Have I forgotten anything, Pete?

[wEEzEr]

thank you very very very very very very very much... :)
you're my idol...

[Pete]

He has lived here for ten years. For = a duration of time, a number of years, etc.
He has lived here since 2001. Since establishes the beginning time.
He has already purchased his ticket/He has purchased his ticket already. Already = before now.
He has not purchased his ticket yet/He has not yet purchased his ticket. Not yet + present perfect = At any time in the past, up to the present.

This may be over-simplified. Have I forgotten anything, Pete?
Hi Rusty- These examples and explanations sound fine to me -- I can't think of anything to add.