电气化铁路的输电线常用图所示的方式悬挂在钢缆上.钢缆的A端固定在电杆上,B端连接

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问题:

电气化铁路的输电线常用图所示的方式悬挂在钢缆上.钢缆的A端固定在电杆上,B端连接在滑轮组上.滑轮组由a、b、c三个滑轮构成,配重P由多个混凝土圆盘悬挂在一起组成,配重的总重为G,若不计摩擦和滑轮的重量,则以下说法中正确的是(  )

A.a为动滑轮,B端钢缆受到滑轮组的拉力大小约为3G

B.a为动滑轮,B端钢缆受到滑轮组的拉力大小约为G

C.a、c为动滑轮,B端钢缆受到滑轮组的拉力大小约为3G

D.a、c为动滑轮,B端钢缆受到滑轮组的拉力大小约为G

考点:定滑轮及其工作特点动滑轮及其工作特点
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我会连。

拍皮球      踢足球      打篮球

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What is the best way to study? This is a very important question. Some Chinese students often  36  very hard  37  long hours. This is a   38 habit(习惯), but it is not a better way to study.  A good student must 39 enough sleep, enough food and enough rest.          

Every  40  you   41   to take a walk or play basketball or ping-pong or sing a song. When you  42   to your studies, you’ll find yourself   43   than before and you’ll learn more.

Perhaps we can  44  that learning English is like taking Chinese medicine, We mean that like Chinese medicine, the effects(效果) of your study   45   slowly but surely. Learn every day and effects will come just like Chinese medicine.

小题1:A. play           B. study              C. sleep         

小题2:A. at                 B. in                   C. for            

小题3: A. best           B. better           C. good           

小题4: A. have            B. do                  C. want          

小题5: A. day             B. week             C. hour             

小题6: A. want           B. hope               C. need

小题7:A. begin          B. return            C. go             

小题8: A. stronger            B. weaker           C. strong

小题9:A. say               B. guess             C. talk               

小题10:A. return            B. come          C. give

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患者男,8个月。上前牙未萌出。体检颌面部发育正常,对称,上颌左右乳中切牙局部牙龈颜色正常,扪无明显隆起,临床处理应选择()。

A.拍曲面体层片

B.增加营养

C.切开导萌

D.局部用药

E.观察

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软件设计模块化的目的是______程序设计的复杂性。

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建立质量成本管理流程

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