阅读短文，从每题所给的ABC三个选项中选出最佳答案回答问题或完成句子。
When the traffic lights turn red, we will stop driving a car or crossing a street. Why is red used for traffic lights instead of other colors?
As we know, scattering (散射) happens when light goes through the air. For the same media(媒质), if the wavelength islong, the scattering will be short. If the wavelength is short, then the scattering will be long.
Of all lights we can see red has the longest wavelength, so the scattering is the weakest. That means the red light travels far. In fact, it travels farther on rainy days.
Using the red light can help drivers in farther areas sec the lights. It helps drivers stow down or stop in lime. If drivers don't see the red light until they are close, they may not be able to stop the car in time. An accident may happen Red can also excite people. We can act more quickly when we see the color red. In a word, red lights help drivers stop in time and help prevent accidents.
小题1:When the traffic lights turn ______, we will stop driving a car.
A. red B green C. yellow
小题2:According to the passage, the scattering of the red light is the _______.
A. longest b. weakest C. farthest
小题3:The underlined word "wavelength" means________ in Chinese.
A.波浪 B.光波 C.波长
小题4:What can the red light help drivers do?
A. It can help drivers in farther areas see the lights.
b. It can help drivers slow down or stop in time.
C. A and b
小题5:Which of the following is the best title?
A. Why do accidents happen
b. How does the red light travel
C. Why do we use red traffic lights
小题1:A
小题2:B
小题3:C
小题4:C
小题5:C
题目分析：这篇短文主要介绍了在交通灯变成红灯时我们就会停止停止开车和过马路，为什么交通灯会设计成红色而不是其他的颜色呢？文章给我们进行了解释。
小题1:细节理解题。根据第一段的第一句：When the traffic lights turn red. we will stop driving a car or crossing a street.可知。故选A
小题2:细节理解题。根据第三段的第一句 ：Of all lights we can see red has the longest wavelength, so the scattering is the weakest.可知。故选B。
小题3:词意猜测题。根据句意为：如果波长长，那么散射短。故选C
小题4:细节理解题。根据最后一段的第一句 ：Using the red light can help drivers in farther areas see the lights, it helps drivers stow down or stop in time. 可知，故选C
小题5:归纳理解题。根据由本文的第一段提出问题：Why is red used for traffic lights instead of other colors? 可知，故选C