我国目前在牵引计算中考虑到的附加阻力主要有()。 A.风力 B.坡度阻力 C.曲线阻

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问题:

我国目前在牵引计算中考虑到的附加阻力主要有()。

A.风力

B.坡度阻力

C.曲线阻力

D.起动阻力

E.隧道阻力

考点:铁路知识考试铁路知识考试综合练习铁路知识考试综合练习题库
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下列不是招标阶段进度的内容的是( )。

A.招标、评标

B.施工进度目标规划

C.项目采购进度规划

D.项目采购进度控制

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对具有四级结构的蛋白质进行一级结构分析时

A.只有一个自由的α氨基和自由的α羧基

B.只有自由的α羧基,没有自由的α氨基

C.只有自由的α氨基,没有自由的α羧基

D.有一个以上的自由α氨基和α羧基

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B

Escaping a fire is a serious matter: knowing what to do during a fire can save life. It is important to know the way you can use and show them to everyone in the family, such as stairs and fire escapes, but not lifts. From the lower floors of building, escape through windows is possible. Learn the best way of leaving by window with the least chance of serious injury.

The second floor window is usually not very high from the ground. A person of average height, hanging by the fingertips will have a drop of about 6 feet to the ground. It is about the height of an average man. Of course, it is safer to jump a short way than to stay in a burning building.

Windows are also very useful when you are waiting for help. Be sure to keep the door closed before opening the window. Otherwise, smoke and fire may be drawn into the room. Keep your head low at the window to be sure you get enough fresh air rather than smoke that may have leaked into the room.

On a second or third floor, the best windows for escape are those which open onto a roof. From the roof a person can drop to the ground more safely. Dropping onto the cement might end in injury. Bushes and grass can help to break a fall.

69. Which of the following people seldom use when trying to escape a fire?

A. Windows.                        B. Doors.                                   C. Fire escapes.             D. Lifts.

70. How far from the ground to the second floor window?

A. About 12 feet.                                                           B. About 3 feet.

C. Nearly 10 feet.                                                           D. About height of an average man.

71. The writer tells us that ______.

breathing in smoke might not be harmful

smoke will enter the room by an open window

fresh air can’t reach the second floor

to keep your head low will help you escape a fire

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置换焊补就是利用惰性介质将原有的可燃物彻底置换排出,使容器内的可燃物含量降低到安全值,从而保证焊补时安全。

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表示某现象发生的频率或强度用

A.构成比
B.指标
C.观察单位
D.率
E.百分比

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