TIME EXPRESSIONS used with the Present Perfect:
justThey have just seen  him.
alreadyThey have already seen him.
everHave they ever seen him?
neverThey have never seen him.
They haven’t seen him yet.
Have they seen him yet?
stillThey still haven’t seen him.
sinceThey haven’t seen him since June.
forThey haven’t seen him for 6 months.
They haven’t seen him lately/recently.
this morning (this week, today...)They have seen him this morning.
once (twice, three times,...)They have seen him three times.
so far (up to now)They haven’t seen him so far.
How much (How many)How many times have they seen him?
How longHow long have they seen him?
beforeThey have seen him before.
  • We usually use the words just/already/ever/never before the past participle (the 3rd form of the verb):
    I have just spoken to Carl.
    They have already 
    done this task.
    Have they ever been to New York?
    She has never seen this film.
  • We use the word yet at the end of the negative or interrogative sentences.
    They haven’t finished their project yet.
    Have your parents arrived yet?

  • We use the word still before "have/has" in negative sentences.
    I still
    haven’t done it.