The foreign teacher Mr. Halt has a strange way of writing. Here’s a notice from him, but no clear ______ of what he has written can be made at all.

A．explanation

B．meaning

C．idea

D．sense

发电机在手动并列操作中，要求离同期点提前一个角度合入发电机断路器，此角度所确定的时间，应等于（）的时间。

A、断路器固有合闸；

B、继电保护动作；

C、发合闸脉冲到断路器合入；

D、操作。