Question

---Your classroom report is so wonderful.
---I wrote for 3 hours ___________ I finished it

1. A.
   when
2. B.
   if
3. C.
   before
4. D.
   after

Answer 1

C
考查从句的连接词。“你的课堂报告很精彩。”“我花了3小时完成它的。”A“当”；B“如果”；C“在......之前”；D“在......之后”。故选C。