Question

---I don’t suppose they could have finished their experiment,______ they?
---______, they are still doing it in the lab.

1. A.
   could; Yes
2. B.
   didn’t; No
3. C.
   have; No
4. D.
   couldn’t; Yes

Answer 1

C
本题考查反义疑问句。句中主语为第一人称，且为否定，故从句为否定转移，故用have they.句意：——我认为他们不可能完成他们的实验，是吗？——是的，他们仍然在实验室做实验。