老师挥手示意学生们安静下来。

The teacher is ___signaling the students to be quiet by waving her hand.

他通过挥手向我们示意可以开始了。

He is ___signaling us to start by waving his hand.

交通灯正通过红色闪烁向司机发送停止信号。

The traffic light is ___signaling drivers to stop with its red flash.