这是迄今完全没错的答案：
1.I haven't played the basketball for a long time. The last time I played basketball was two weeks ago. [假定是篮球,也可改成footfall, volleyball, badminton, etc.]
2.This school was built 15 years ago; many teachers have been working here since it was founded.
3.How come you havn't finished your homework? I finished mine two hours ago.
4.He has worked in the hospital for five years; he came to Shengzhen in 2004.