When do you use for, since and ago?
1/ I'm still waiting for her... I've been waiting --- 30 minutes...
2/ He hasn't come here --- 3 years.
3/ They finished sleeping 15 minutes ---.
4/ I've been playing the flute --- 3 o'clock.
5/ I've been playing the piano --- 7 years.
6/ He stopped smoking 6 years ---.
7/ --- when have you lived here?
8/ Have they been waiting --- a long time?
9/ He studied geography 5 years ---.
10/ We have come to this restaurant --- a decade.