潜影的组成成分是A．感光中心B．显影中心C．银离子D．溴离子E．电子

在有分布式电源接入的低压配电网上工作，宜（）。

A.采取停电工作方式

B.采取带电工作方式

C.使用低压第一种工作票

D.使用低压带电作业工作票

The boy sat there quietly, ______ eyes were filled with tears.

A．whose

B．with whose

C．his

D．of whom

— Did Betty go shopping with you yesterday?

— Even if she _____ a lot of studying, she would have preferred staying home to going shopping. [ ]

A. didn't have

B. shouldn't have

C. hadn't had

D. hasn't had

危机干预服务最常用的方式是面淡。 ( )

什么是调节器的动作规律？目前发电厂中普遍应用的主要有哪几种调节规律？