Signal red的意思|示意

Thus, green became "go," and for a long time, railways used only green and red to signal trains.

因此，绿灯成为了“通行”的标志，长期以来铁路也只将红色和绿色作为信号灯。

Using the natural reflectivity of ceilings and walls, a transmitted infra-red signal can be received by any number of receivers within a room.

利用天花板和墙面的自然反射性，传送的红外信号能够被一个屋子里的所有接收器接收到。

August 14th, 1963, at a lonely spot outside London, the Glasgow to London mail train was halted by a red signal and ambushed by 15 masked men.

八月十四号，在一个远离伦敦的冷清地点，从Glasgow道伦敦的火车被一个同样装束的15个蒙面人劫持了。

A red light is a signal of danger.

红灯是危险的信号。

Red balloons trapped between the two layers of mesh signal the entrances to the pavilion, which is accessed through triangular metal openings.

两层网中间夹着红色的气球，为场馆三角形的金属入口提供标志。

Outside his boardroom he posted red and green lights to signal to his secretary whether visitors could enter.

他在会议室的外面用红光和绿光来暗示秘书是否该让来访者进来。