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.  
Where can we most probably read this text?

选项 A、In a research paper,
B、In a short story.
C、In a travel magazine.
D、In a student’s book.

答案D

解析 由常识可知,本文是一篇科普文,介绍了一些科学知识,所以D(学生课本)比较合适。而A中的research paper意为“研究论文”;B中的a short story意为“短片故事”;C中的travel magazine意为“旅游杂志”。
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