– You won the first prize in the physics contest ! ! I made several terrible mistakes

问题补充：

– You won the first prize in the physics contest !

-- ! I made several terrible mistakes .

A. I think so

B. You must be joking

C. You must be serious

D. I’m afraid so

答案：

A. I think so

(答案→)B. You must be joking

C. You must be serious

D. I’m afraid so

解析：A. .我认为如此 B.你一定在开玩笑吧 C. .你一定是认真的。D. 我恐怕如此。 句意：你在物理竞赛上获得一等奖了！—你在开玩笑吧！我犯了几个严重的错误。结合题意，故选B。