1．may/might have missed　由"I am not sure"可知空处表示不太肯定的推测，故用may/might have done。

　　2．should have been　should have done表示"本应该做某事而实际上没做"。

　　3．can't/couldn't have stayed　由"She doesn't know your address"可知，空处表示否定的推测，故用can't/couldn't have done。

　　4．must have received　因为书是三周前寄出的，因此她肯定已经收到了。must have done 表示肯定的推测，用于肯定句中。

　　5．must have passed　由上一句中的"happy"和下一句中的"not difficult after all"可以推知，此处表示肯定的推测，故用must have done。

　　6．needn't have taken　句意：结果昨天天气不错，我本没有必要随身带把伞。needn't have done表示"本不必做某事(而实际上做了)"。

　　7．needn't have come　句意：既然你昨天工作到那么晚，今天早上你就没必要来了。

　　8．might/may have failed　从语境分析，此处表示对过去可能发生的事情的推测，故用may/might have done。

　　9．ought to/should have come　由"but why didn't you"判断，空处应用ought to/should have done 结构，表示"本应该做某事而实际上没做"。

Ⅱ.完成句子

1．-Mummy，I climbed to get the teddy bear from the top of the shelf.