手持式用电设备及移动设备，不应安装漏电保护器作为末级保护。第

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问题判断题

手持式用电设备及移动设备，不应安装漏电保护器作为末级保护。第五章P82

答案

参考答案：错

选择题

My sister met him at the Grand Theatre yesterday aftemoon , so he _____ your lecture. [ ]

A. couldn't have attended

B. needn't have attended

C. mustn't have attended

D. shouldn't have attended

问答题

简述根管治疗的适应证。