— Guess what! I have won the first prize in the speaking petition.
— Congratulations! You put a lot of work into it.
A. should
B. must
C. should have
D. must have
网友回答
A. should
B. must
C. should have
D. must have
解析：考查情态动词。句意 猜猜看，我记得演讲比赛第一名。祝贺你，你肯定是投入很多精力在这上面。根据上文提到已经取得成功，故表示对过去的肯定推测 ，所以选D项。
考点 : 考查情态动词