读一读，选词填空。

1. It's time ____________ (to / for) go to school.

2. It's time ____________ (to / for) go home.

3. What time ____________ (is it / are they)?

4. I can see two ____________ (clock / clocks).

5. School is ____________ (over / ready).

电拉闸操作必须按照（）--（）--（）的顺序依次操作，送电合闸作应按与上述相反的顺序进行。严防带负荷拉合（）。为防止误操作，高压电气设备都应加装（）。