He didn't come yesterday． He __________&n-考呗网题库移动版

单选题He didn't come yesterday． He __________ busy working in the lab.

A． must be
B． would have been
C． must have been
D． would be

参考答案C

解析:译文：他昨天没来，一定是在实验室里忙着呢。
情态动词题。must+have been／done用来推测过去发生的动作或存在的状态；must+be／do用来表示对现在发生的动作或存在的状态进行推测。本句中，因为动作发生在过去，故应用must+have been这种形式。

单选题__________, I will take her as my wife．

A． Were she rich or poor
B． Being rich or poor
C． Be she poor or rich
D． Whether is she poor or rich

单选题All the flights __________ because of the extremely heavy rain，we had to postpone our schedule．

A．were canceled
B．had been canceled
C．having canceled
D．having been canceled

单选题He ought to dismiss the unqualified employees under his supervision, __________?

A．should he
B． ought he
C． shouldn't he
D． oughtn't he