英语小问题

Question

用情态动词“used to,had better, must, mustn't, will, may, couldn't, should, would"填空
"Where is my umbrella?"Somebody _______ have taken it away by mistake.
拜托说明理由

Answer 1

Where is my umbrella?"Somebody _must_ have taken it away by mistake.这里肯定要用must，一个最根本的原因是：推断过去发生的事情必须用must have done,题目中我的雨伞不见肯定是过去发生的事情了。

Answer 2

must 表肯定