What is colour? Why do some of the things around us look red, others green, others blue?

　　Colours come from reflected（反射）light. We can see colours because some of the things reflect light. Something is red, because it reflects most of the red light. In the same way, if something is green, it reflects most of the green light. If something reflects all light, it is white. If something doesn't reflect any light, it is black.

　　Some light is not reflected（不被反射）. It is taken in（被吸收）and turned into heat（变成熟）. If the colour is darker, it reflects less light, and takes in more light.

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What is the sky？ Where is it？ How bright is it？ What lies above it？ These questions are difficult to answer, aren’t they？

　　Is the sky blue？ The sky has no color. We know that there is air around the world. When planes fly, they need air to lift their wings. Planes can’t fly very high because the air gets thinner when they go up higher. If we go up about 1,200 kilometers from the earth, we’ll find no air there.

　　When we talk about the sky, we usually mean the atmosphere around the earth. It is like a very thick “cover” over the earth and keeps it warm. Without the “cover”, the earth would be a very cold place and nothing could live on it.

　　Looking up above us, you will see the blue sky with white clouds. It is usually light blue, but the sky would be dark blue if you go to the top of the highest mountains. And you will see fewer clouds between you and the sun.

　　And if you sit in a spaceship high above the earth, there is no air at all. The sky would be so dark that its color would be black.

　　Sometimes the sky doesn’t look blue. When the sun rises and falls, you will see red, orange, and other colors in the sky. These are the most beautiful moments of the day.

　　Now you may understand that we see colors because the air scatters (散射) the sunlight. Light travels through the air. Without air, there would be no light and no colors.

1.Planes can’t fly very high because ____________.

A．there is air around the world

B．the air gets thinner when they go up higher

C．it’s warmer in the sky

D．the air gets thicker when they go up higher

2.We can see colors of the sky because ____________.

A．the sun rises and falls every day

B．the sky has lots of colors

C．the air scatters the sunlight

D．the sunlight has many colors

3.Which of the following is TRUE？

A．There is little air without light and colors in the sky.

B．The sky will look red, orange and other colors at noon.

C．The sky has only one color when the sun rises and falls.

D．The sky is dark blue if you go to the top of the highest mountains.

阅读理解（每小题2分，共10分）

　根据以上内容，选择最佳答案。

1._______ finds (找到) a watch.

A. David            B. Jessica     C. Judy

2.What’s the color of the watch?

A. Black         B.. White.      C. Red.

3.__________ school card is lost.

A. Jessica’s      B. David’s      C. Judy’s

4.Jane’s watch is lost; she should (应该) call ______________.

A. 33073061           B. 33429703     C. 36206018

5.Tim finds(找到) David’s card; he should call ______________.

A. 20070107                   B. 36206018       C. 33429703

Pearl and June were good friends and spent most of their time together.

They were both very old and they worried about their health. Most of the time they talked about nothing else.

They worried about their food. Was it clean? Would it give them pains in the stomach?

They worried about the weather. Was it too cold and wet? Would it give them pains in their bones?

They worried about pollution in the air. would it give them pains in their chests(胸部)and throats(喉咙)?

They worried about being hurt in a car accident, killed in a plane crash, getting sick, and so on.

All they could think about was being ill or hurt.

One day they went on a train journey together.

“We’ll need some food,”Pearl said.

“We’ll buy some bananas,”June said.“They are good to eat and always clean.”

And so they bought two bananas to eat on the train.

It was not long before they were hungry.

Pearl took out the bananas and gave one to June. Then she peeled(剥)the skin of her banana and took a large bite of it.

At that moment the train went into a tunnel. Everything went black.“Don’t eat your banana,”Pearl shouted at June.“Mine has made me go blind!”

1.What did the two old ladies talk about most of the time? _________

A. Themselves.      B. Other people.       C. Healthy food.       D. Dangerous drivers.

2. The old ladies didn’t want to ______.

  A. eat any bananas                       B. travel by train

  C. be young again                        D. get sick

3.Pearl ate her banana ________.

  A. after they came out of the tunnel       B. at the station

  C. before June ate hers                    D. before she was hungry

4. Pearl thought that the banana _______.

  A. stopped her from seeing                B. would make her hungry

  C. would make her ill                     D. would be good for June

5.What’s the best title of the story? __________.

  A. What Good Friends                   B. What a Bad Train Journey

  C. Bananas Are Good for You            D. Bananas Are Bad for You