Underline the correct answer. 1 We've been here for / since last week.
2 I've known Alice for / since we started going to the same school
3 David's played the piano for / since five years.
4 Mum's been out for / since 10 o'clock.
5 I haven't seen Monica for / since a few days.
1) For
2) since
3) for
4) for
5) for