Question

       Have you ever wondered?

   1. Why do airplanes take longer to fly west than east?

   It can take five hours to go west-east from New York (NY) to London but seven hours to travel east-west from London to NY. The reason for the difference iwS an atmospheric phenomenon (现象) known as the jet (喷射) stream. The jet stream is a very high altitude (髙度) wind which always blows from the west to the east across the Atlantic. The planes moving at a constant air speed thus go faster in the west-east direction when they are moving with the wind than in the opposite direction.

    2. What would happen if the gravity (地心引力) on Earth was suddenly turned off?

    Suppose we could magically turn off gravity. Would buildings and other structures (建筑物) float away? What happened would depend on how strongly the things were attached to the Earth. The Earth is moving at quite a speed,moving at over a thousand miles per hour. If you turn something around your head on a string (细绳) ，it goes around in a circle until you let go of the string. Then it flies off in a straight line. “Switching off” gravity would be like letting go of the string. Things not attached to the Earth would fly off in a straight line. People in buildings would suddenly shoot upwards at a great speed until they hit the ceiling. Most things outside would fly off into space.

() 1. What information can we get from the first passage?

   A. It is the jet stream that affects how fast airplanes fly.

   B. Planes go slower when they are moving with the wind.

   C. It takes more time to fly from NY to London than from London to NY.

   D. The jet stream always blows from the east to the west across the Atlantic.

() 2. The word “shoot” underlined in the 2nd passage probably means “ ”.

   A. send for   B. move quickly   C. come out   D. grow quickly

() 3. It can be inferred that without gravity .

   A. buildings and other structures would float away

   B. trees and buildings would not so easily fly off

   C. something around your head would not float away

   D. everything outside buildings would fly off into space

() 4. Which of the following statements is not mentioned in the passage?

   A. It takes seven hours to travel from London to New York.

   B. The earth is moving at a high speed.

   C. Everything on the earth will float away if there's no gravity.

   D. Everything not attached to the earth would fly off in a straight line.

() 5. Where can we most probably read this text?

   A. In a research paper. B. In a short story. 

    C. In a travel magazine. D. In a student's book.

Answer 1

1. A 2. B 3. B 4. C 5. A

[解析]这篇短文主要通过两个问题——为什么飞机向西飞行比向东飞行用时间长，如果地球引力突

然消失，会发生什么事，来告诉我们地球引力对于我们生活的重要作用。

1. A 根据第一段 The reason for the difference is an atmospheric phenomenon known as the jet (喷射) stream.及下文描述，可知选A.

2. B 联系下文 at a great speed until they hit the ceiling.可知此处指的是快速移动的意思，故选B.

3. B根据短文最后一段描述，可知树木和建筑物由 于与地球相连，故不是能够很容易的飘走，故选B.

4. C 根据短文最后一段 Things not attached to the Earth would fly off in a straight line.描述，可知没 有与地球联系的事物会飘走，故选C.

5. A这篇短文主要探讨了地球引力的问题，故最 有可能来自一篇研究论文，故选A.