One afternoon Mr. Black went out to look for some grass for his cows. It was very hot and he had to stop to have a swim. Suddenly he saw something sparkling（闪闪发光）in the water. He swam there and found it was some gold in the sand. He was so happy that he hardly forgot he was in the river. He ran home and asked his son to help him to get all the gold out of the water. The next morning he sent his son to sell it in the market. But the young man was afraid to do it. He had to go to the town himself. He didn't pay any attention to the traffic lights when he crossed the street. A car hit him down and he was hurt. He was sent to hospital at once. The doctors looked him over and gave him an operation. Two months later he felt much better. The doctors were satisfied with the operation and said, “You'll be fully recovered in a week. We're sure you can write with your right hand when you leave hospital.”

　　“It's really a miracle（奇迹）!”  shouted Mr. Black.  “I could neither read nor write before!”

根据短文内容选择正确答案。

1. The Blacks have little food because________.

A. they live in a small village

B. they're too lazy to work

C. they have few pieces of fields

D. nobody would help them to get money

2. Mr. Black jumped into the river because________.

A. he wanted to get some grass in the water

B. he wanted to look for some gold in the water

C. he hoped to have a good rest in the water

D. it was too hot and he wanted to have a swim

3. Mr. Black ran home to ________.

A. ask for help　　　　　　　　    B. make his family happy

C. change his wet clothes　　　　　　 D. send the gold back

4.　　   Mr. Black's ________ was hurt in the traffic accident.

A. head　　　　   B. leg　　　　　　  C. right hand　　   D. left hand

5.　　   The phrase “be fully recovered” means ________ in Chinese.

A. 完全覆盖　　   B. 全部找回　　    C. 清除疲劳　　   D. 恢复健康

If we are driving a car or crossing a street, we will stop when the traffic lights turn red. Why do we use red rather than other colors?
As we know, scattering (散射) happens when light goes through the air. For the same media, if the wavelength (波长) is long, the scattering will be short. If the wavelength is short, then the scattering will be long.
Of all light 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 see the lights. It helps drivers slow down or stop in time. 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 light helps drivers stop in time and help prevent accidents.
【小题1】______ has the longest wavelength of all light we can see.

If we are driving a car or crossing a street, we will stop when the traffic lights turn red. Why do we use red rather than other colors?

As we know, scattering (散射) happens when light goes through the air. For the same media, if the wavelength (波长) is long, the scattering will be short. If the wavelength is short, then the scattering will be long.

Of all light 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 see the lights. It helps drivers slow down or stop in time. 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 light helps drivers stop in time and help prevent accidents.

1.______ has the longest wavelength of all light we can see.

A. Red               B. Green           C. Yellow          D. Black

2.Red light travels farther on ______ days.

A. windy             B. sunny           C. rainy         D. cloudy

3.Red can make people act more quickly because ____________.

A. red can make people happier              B. the scattering of red is very short

C. the scattering of red is very long           D. red can make people more excited

4.The underlined word “prevent” means ______ in Chinese.

    A.逃避               B. 防止            C. 处理         D. 检查

5.The passage mainly tells us ____________.

A. why accidents happen                     B. how the red light travels

C. why we use red traffic lights               D. how to stop in time at traffic lights