问题
填空题
用 Since或for填空。
1. I've been practicing the piano 10：30
.2. I've been waiting half an hour.
3. He has been living here 1999.
4. Mike has been running 10 minutes.
5. He has been working here he came here.
6. Jim has been talking with Tom two hours.
答案
1. since. 2. for 3. since 4. for，5. since 6.for