Present perfect with how long; simple past with when; since and for в английском языке

Use the simple past (I did) to ask or say when something happened:

  • A: When did it start raining?

  • B: It started raining at one o'clock/an hour ago.

  • A: When did Joe and Carol first meet?

  • B: They first met when they were in college/a long time ago.

Use the present perfect (I have done/I have been doing) to ask or say how long something has been happening (up to the present):

  • A: How long has it been raining?

  • B: It's been raining since one o'clock/for an hour.

  • A: How long have Joe and Carol known each other?

  • B: They've known each other since they were in college/for a long time.

Since and for
We use both since and for to say how long something has been happening:

  • I've been waiting for you since 8 o'clock.

  • I've been waiting for you for two hours.

  • We use since when we say the beginning of the period (8 o'clock).
    We use for when we say the period of time (two hours).



    8 o'clock
    May 12

    we arrived

    two hours
    ten minutes
    three days
    six months

    a week
    five years
    a long time

  • She's been working here since April. ( = from April until now)
    She's been working here for six months. (not since six months)
  • I haven't seen Tom since Monday. ( = from Monday until now)
    I haven't seen Tom for three days. (not since three days)

We do not use for in expressions with all (all day/all morning/all week/all my life, etc.):

  • I've lived here all my life. (not for all my life)

Note the structure How long has it been since... ?:

  • A: How long has it been since you had a vacation?
  • B: It's been (= it has been) two years since I had a vacation. (= I haven't had a vacation for two years.)

  • It's been ages since Aunt Helen visited us. ( = She hasn't visited us for ages.)