Had you joined the chat room ten minutes ago，you would have known what we

                about then．

A．had talked

B．have talked

C．talk

D．were talking

主AC汇流条失效时有什么现象？

A、电瓶充电失效灯亮。

B、AC RESET　灯亮。

C、汇流不会被供电。

D、以上都是。