用since和for填空.
1.______ two years 2._______ two years ago 3._______ last month 4.______ 1999 5._______ yesterday 6._______ 4 o’clock
7.______ 4 hours 8._______ an hour ago 9._______ we were children
10._____ lunch time 11.______ she left here
12.He has lived in Nanjing ________ the year before last.
13.I’ve known him __________ we were children.
14.Our teacher has studied Japanese _________ three years.
15.She has been away from the city ___________ about ten years.
16.It’s about ten years __________ she left the city.