Question

He can't find his key. He ---------- them. A. must lost B. must have been lost C.must have lost

Answer 1

He can't find his key. He ---C------- them.
A. must lost B. must have been lost C.must have lost

must have done表推测已经发生的事情，“一定已经做过某事”
A 错误 应该是must +动词原形
B 错误 must have been lost 被动结构，“肯定被丢失”，而句子主语是He，指人
故选C

Answer 2

C
must have done 固定句型, 一定是...
他找不到他钥匙了.他一定是丢了.
~~~~~~~~~~～～~~~~祝你进步，如对你有帮助，请及时采纳~~~~~~~~~~~~~~~~

Answer 3

C

Answer 4

c