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问题 单项选择题

金属基底冠桥的预氧化应在除气基础上再加热至预定终点温度，在非真空状态下继续维持

A．0.5～1.0min
B．1～3min
C．5～10min
D．20～30min
E．30min以上

答案

参考答案：C

单项选择题

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 ply 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.

It can be inferred that without gravity（）.

A. buildings and other structures would float away

B. trees and buildings would not easily fly off

C. something around your head would not fly away

D. everything outside buildings would fly off into space
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判断题

我国的会计法律制度由会计法律、会计部门规章和会计规范性文件3个层次构成。（）
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