2019版高考英语大一轮复习 第一部分 Module 1 Life in the future课下作业 外研版必修4

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 the 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 1915 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, 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.

【语篇导读】 本文是一篇说明文。交通信号灯为什么是红、黄、绿三种颜色呢？本文主要介绍了交通信号灯的起源和发展。

8.What were traffic lights originally intended for? A.Trains. C.Planes.

B.Cars. D.Ships.

答案 A [细节理解题。根据第一段中的“The answer lies in the fact...for trains, not cars.”可知， 最初， 交通信号灯是为火车而不是汽车的通行而设计的。故选A。] 9.What’s the main reason for red’s long being used to mean “stop”？

A.It can be seen even in dark areas. B.It represents danger in many cultures. C.It has the longest wavelength. D.People prefer red to other colors.

答案 C [细节理解题。根据第二段中的“As red has...than other colors.”可知， 由于红色在可见光谱中波长最长， 因此可视距离要比其他颜色更远，这也是其能长期被用作表示“停止”的交通信号的原因。故选C。]

10.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 lights has changed over time.

答案 D [推理判断题。根据第三段的内容尤其是“green meant ‘caution ’”“green became ‘go’”可知， 随着时间的变化，绿色在交通信号灯中所扮演的角色也发生了巨大的变化。故选D。]

11.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.

答案 D [主旨大意题。通读全文内容可知， 本文主要讲述了交通信号灯的起源与发展， 并解释了这三种颜色(红、黄、绿)的物理性质及为什么会被用作交通信号灯。故D项最为全面地概括了文章的主要内容。]