提升作用的条件是:两针面平行配置,有相对运动且一针面的针齿工作面迎着另一针面的齿背面

题型:判断题

问题:

提升作用的条件是:两针面平行配置,有相对运动且一针面的针齿工作面迎着另一针面的齿背面,,两针面隔距很小。

考点:纺纱工艺纺纱工艺题库
题型:判断题

London used to be “foggy”( 有雾的) for the same reason that cities like Beijing or Chongqing are “foggy” today. The “fog” was in fact smog(烟雾), a mixture of smoke and fog.In other words, it was made by air pollution. In London, some of this pollution came from factories, but much of it came from the coal(煤)that people burnt in their houses to keep warm during the winter. By the 1950s, London’s smog problem had become so bad that the government decided to do something to clean the air. A new law was made and nobody could burn coal in any British city. In a few years, the air became much cleaner. There were no more “pea-soupers”.

Many Chinese cities now face the same sort of problem with air pollution that London faced 40 or 50 years ago. However, this problem is more difficult for Chinese cities to solve. One reason is that more of the pollution comes from the factories, rather than from coal burnt in people’s houses. If these factories were closed, this would harm the economy and lots of people would lose their jobs. Another reason is that changing from coal to cleaner fuel(燃料), like gas, is quite expensive.

However, the air in many Chinese cities is becoming cleaner and cleaner, as the government and people pay more and more attention to cutting down pollution. As a result, there are fewer “pea-soupers” in Beijing than there used to be.

小题1:What was the main reason for air pollution in London?

A.There was too much smoke in the sky.

B.There were too many factories in the city.

C.People burnt too much coal in the houses.

D.The city was too big for the cleaners to clean.小题2:What does the underlined word “pea-soupers” refer to?

A.Smog

B.Smoke

C.Gas

D.Coal小题3:Which sentence is Not true?

A.Air pollution is serious in Beijing and Chongqing.

B.Using coal is much more expensive than using gas.

C.Factories made much more pollution in China.

D.The reasons of air pollution in London and Beijing are different

题型:判断题

()现象可以随机器转速变化,振动突升或突降。——

A.不平衡

B.共振

C.拍振

D.齿轮故障

题型:判断题

为了预防排斥反应,器官移植前应作的检查是()

A.ABO血型

B.淋巴细胞毒交叉配合试验

C.HLA配型

D.混合淋巴细胞培养

E.血小板抗原检测

题型:判断题

利尿剂的主要不良反应是

A.体位性低血压

B.高血压反跳

C.刺激性干咳

D.离子紊乱

E.水钠潴留

题型:判断题

根据我国机动车辆保险条款的规定,保险车辆如果续保时可以享受无赔款优待,有待比例最高不超过()

A、10%

B、20%

C、30%

D、50%

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