问题
选择题
— Guess what! I have won the first prize in the speaking competition.
— Congratulations! You _____ put a lot of work into it.
A．should
B．must
C．should have
D．must have
答案
D
题目分析：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