Question

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.

 

Answer 1

【答案】

 

1.B

2.C

3.D

【解析】

試題分析：在這篇短文里，講述了為什么天空會呈現(xiàn)不同的顏色。那是因為空氣散射光線的結(jié)果。例如越高空氣越稀薄，在高山頂上看到天空是深藍色，在太空看到天空是黑色的等。

1.細節(jié)理解題。文中第一段Planes can’t fly very high because the air gets thinner when they go up higher.飛機不能飛得太高，因為越高空氣越稀薄，故選B。

2.判斷推理題。文章最后一段Now you may understand that we see colors because the air scatters (散射) the sunlight. Light travels through the air現(xiàn)在你或許明白我們看到顏色是因為空氣散射太陽光，而光線穿過空氣。由此判斷我們看到有顏色的天空是因為空氣散射的原因，故選C。

3.判斷推理題。文章第四段but the sky would be dark blue if you go to the top of the highest mountains.但是當你爬到最高山頂時，天空是深藍色的，故判斷D正確。

考點：科普類短文閱讀。