Question

11. —Show me your permit, please.

―Oh, it's not in my pocket. It    .

A.    must have fallen out

B.    might fall out

C.    could fall out

D.    should have fallen out

Answer 1

11.   A 考查"情态动词+ have done"结构。must have done表示对过去发生的事情进行有把握的推测，意为"一定做过"， must have fallen out表示fall out这个动作在说话之前已经发生了。由此可知表示推测，排除D;表示动作过去巳发生， 排除B、C。句意："请出示您的许可证。""哦，它不在我的口袋里，一定是掉了。"

【拓展延伸】"情态动词+ have done"—定是与过去相关，有

两种含义.

CD对过去情况的猜测，如：

must have done(肯定做过了 )

can't have done(不可'能做过 )

may/might/could have done(可能做过了)

(2)与过去事实相反，如：

should (not) have done(本该/本不该做)

needn't have done(本不必做  )

might/could have done(本可以/本能够做 ）