signal strength 信号强度
signal loss 信号丢失
signal the change 预示变化
A: How did you know it was time to go?
A：你怎么知道该走了？
B: The bell signalled the end of the class.
B：铃声预示着课程结束了。
1) 传达信号或暗示
2) 预示某种趋势
3) 通过动作示意
1. 示意，发出信号
verb
1. To communicate something using signals, or to be a sign of something.
Synonym: indicate, suggest, denote