—I don’t suppose they could have finished their experiment they?— they are still doing

问题补充：

—I don’t suppose they could have finished their experiment, they?

— , they are still doing it in the lab.

A. could; Yes

B. didn’t; No

C. have; No

D. couldn’t; Yes

答案：

A. could; Yes

B. didn’t; No

(答案→)C. have; No

D. couldn’t; Yes

解析：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。