vt.使顯著；使突出；特別指出；表明；使信號(hào)化

A red light is usually a signal of danger. 紅燈通常是危險(xiǎn)的信號(hào)。

I stood watching for the signal to change to green. 我站著等待交通信號(hào)轉(zhuǎn)為綠燈。

Let's set the clock by the radio time signal. 咱們照著收音機(jī)的報(bào)時(shí)信號(hào)把鐘對(duì)一對(duì)。

A red lamp is often a danger signal. 紅燈常常是危險(xiǎn)的信號(hào)。

A reflected signal on a communication channel. 一種在通信信道上反射回來(lái)的信號(hào)。

The rise in prices was a signal for rebellion. 物價(jià)上漲引起了叛亂。