Question

【题目】Attention, please! All the mobile phones _______ during the meeting.

A. are turn off B. have to turn off

C. should turning off D. must be turned off

Answer 1

【答案】D

【解析】

试题分析：句意：请注意！在开会期间所有的手机都必须要关闭。根据主语和谓语中间是动宾关系，所有用被动语态，其结构是be done.含有情态动词的被动语态的结构是：情态动词 be done。结合句意，故选D。