题目内容
【题目】Attention,please!All the mobile phones must________before the meeting starts.
A.turn off
B.be turned off
C.be turning off
D.turned off
【答案】B
【解析】情态动词的被动语态由“情态动词+be+动词的过去分词”构成。
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题目内容
【题目】Attention,please!All the mobile phones must________before the meeting starts.
A.turn off
B.be turned off
C.be turning off
D.turned off
【答案】B
【解析】情态动词的被动语态由“情态动词+be+动词的过去分词”构成。