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 bu

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问题     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 is an atmospheric phenomenon known as the jet(喷射) stream. The jet stream is a very high altitude 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 on Earth was suddenly turned off?
    Supposing 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 hours. 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 up-wards at a great speed until they hit the ceiling. Most things outside would fly off into space.  
What information can we get from the first passage?

选项 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

答案A

解析 由第一段最后两句可知喷射汽车穿过大西洋时总是从西吹向东,因此飞机顺风飞行比逆风飞行速度快,故推出喷射气流影响飞行速度,故选A。B和第一段最后一句矛盾,句中的slower应该写成faster;C和第一段第一句意思相反,句中的more应该是less:D 中的from the east to the west应该是from the west to the east,故排除。
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