Question

    It is well known to car drivers that red means “stop”, green means “go” and yellow means “hurry up and make that damn light”. Why those colors, though? The answer lies in the fact that the earliest traffic signals were designed for trains, not cars. They were red and green, gas-powered, and more than a little dangerous in the event of a leak.

Red is an inherited (继承的) symbol from railroads, which symbolizes danger in many cultures. As red has a longer wavelength than any other color on the visible spectrum (光谱), it can be seen from a greater distance than other colors. Red has meant “stop” since long before cars existed, with train signals’ use of red dating back to the days when mechanical arms lifted and lowered to indicate whether the rail ahead was clear.

Green’s wavelength is next to (and shorter than) yellow’s on the visible spectrum, meaning it’s still easier to see than any color other than red and yellow. Back in the early days of railway lights, green meant “caution”, while the “all-clear” light was, well, clear or white. It is said that several disastrous collisions happened after an engineer mistook stars in the night for an all-clear. Thus, green became “go”, and for a long time, railways used only green and red to signal trains.

From the earliest days of motoring up until mid-1900s, not all stop signs were red-many were yellow, because at night it was all but impossible to see a red stop sign in a poorly lit area. In 1950 the yellow stop-sign craze began in Detroit, a city that five years later installed its first electric traffic signal, which happened to include the very first yellow traffic light.

But what of those mysterious yellow stop-signs? As materials and technologies evolved, the ability to produce highly reflective signs meant that red could resume its natural spot in the sign hierarchy (层次体系，等级体系), leaving the still-highly-visible yellow to the domain (领域) of “caution”. That’s why school zones and buses, crosswalks, and other important warnings are yellow today.

1.What’s the main reason for the color red’s long being used to mean “stop”?

A.It has the longest wavelength on the visible spectrum.

B.It represents danger in many cultures.

C.It can be seen even in the dark area.

D.People prefer red to other colors.

2.Which of the following may the author agree with?

A.The meaning of red is culture–specific.

B.Yellow functioned as stop signs in the 1900s.

C.Green’s wavelength is just second to that of red.

D.Green’s role in traffic lights has changed over time.

3.What does the passage mainly talk about?

A.The significance of road traffic signs.

B.The history of railroad transportation.

C.The symbolic meaning of different colors.

D.The origin and development of traffic lights.

Answer

1.A

2.D

3.D

【解析】

本文是一篇说明文。我们都知道“红灯停，绿灯行，黄灯亮了快点走”的交通规则。但交通信号灯为什么是红、绿、黄三种颜色呢？本文主要介绍了交通信号灯的起源和发展。

1.

细节理解题。根据第二段中As red has a longer wavelength than any other color on the visible spectrum (光谱), it can be seen from a greater distance than other colors.“由于红色在可见光谱中比其他任何颜色的波长都长，所以它比其他颜色从更远的距离就能被看到。”由此可知，红色长久以来被用来表示“停止”的主要原因是在可见光谱中，它的波长最长。故选A。

2.

推理判断题。根据第三段内容 Back in the early days of railway lights, green meant “caution”, while the “all-clear” light was, well, clear or white. It is said that several disastrous collisions happened after an engineer mistook stars in the night for an all-clear. Thus, green became “go”, and for a long time, railways used only green and red to signal trains.可知，在早期的铁路信号灯时代，绿色代表”警告”而”安全”信号灯是，透明或白色。 据说一位工程师误以为夜晚的星星是安全的，结果发生了几次灾难性的碰撞。 因此，绿色变成了“通行” ，很长一段时间，铁路只用绿色和红色来给火车发信号。由此判断出，作者同意“随着时间的推移，绿色在交通灯中的作用已经发生了变化”。故选D。

3.

主旨大意题。根据第一段It is well known to car drivers that red means “stop”, green means “go” and yellow means “hurry up and make that damn light”. Why those colors, though? The answer lies in the fact that the earliest traffic signals were designed for trains, not cars.我们都知道“红灯停，绿灯行，黄灯亮了快点走”的交通规则。但交通信号灯为什么是红、绿、黄三种颜色呢？答案在于最早的交通信号是为火车而不是汽车设计的。再结合全文队医这三种灯的具体介绍可知，本文主要讲述了交通信号灯的起源与发展，故选D。