这个电器需要一个三脚插头。

This appliance requires a three-pin ___plug.

如果插头接线不正确，可能会很危险。

If a ___plug is wired incorrectly, it can be dangerous.

我们必须检查房间里的每一个插头、开关和灯。

We had to check every ___plug, switch, and light in the room.