Definition: to make a movement that gives information or tells people what to do Level: C2
他向左打信号，然后慢慢转动卡车。
He ___signaled left, then turned the truck slowly.
他正在用一面橙色旗子发信号。
He was ___signaling with an orange flag.
警察示意我们停下。
The police officer ___signaled for us to stop.
