自2010年至今的四级考试中， 共出现过 次
自2010年至今的六级考试中， 共出现过 次
N-COUNT (以手势、声音、行动等发出的)信号，暗号 A signal is a gesture, sound, or action which is intended to give a particular message to the person who sees or hears it.
They fired three distress signals...
As soon as it was dark, Mrs Evans gave the signal...
VERB (用手势、声音等)发信号，发暗号，示意 If you signal to someone, you make a gesture or sound in order to send them a particular message.
The United manager was to be seen frantically signalling to McClair...
He stood up, signalling to the officer that he had finished with his client...
N-COUNT 迹象;信号;预示 If an event or action is a signal of something, it suggests that this thing exists or is going to happen.
Kurdish leaders saw the visit as an important signal of support...
The first warning signals came in March...
VERB 预示;表明;显示 If someone or something signals an event, they suggest that the event is happening or likely to happen.
She will be signalling massive changes in energy policy...
Britain was signalling its readiness to have the embargo lifted...
N-COUNT (铁路上的)指示灯，信号灯 A signal is a piece of equipment beside a railway, which indicates to train drivers whether they should stop the train or not.
N-COUNT (传输信息的无线电、光波或电流)信号 A signal is a series of radio waves, light waves, or changes in electrical current which may carry information.
...high-frequency radio signals.
ADJ 重大的;显要的;非凡的 You use signal to describe a success or failure when you are emphasizing the fact that it has occurred and are indicating that the consequences are significant.
His final round was a signal triumph in a career marked by many sweet moments.
...John Major's signal failure to grab America's attention.