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问题 填空题

如图，在直角三角形支架B端悬挂一10千克的物体，则作用在AB杆上的力为______牛，BC杆上的力为______牛．

答案

以B点研究对象，分析受力情况，作出力图，如图．

根据平衡条件得

  FABcos30°-FBC=0

  FABsin30°-mg=0

解得FAB=200N，FBC=100

3
N

故答案为；200，100

3

单项选择题 A1型题

眶下神经阻滞麻醉口外注射法进针方向是（）

A.注射针与皮肤成60度角，向上、后、外进针

B.注射针与皮肤成45度角，向下、后、外进针

C.注射针与皮肤成45度角，向上、后、外进针

D.注射针与皮肤成45度角，向上、后、内进针

E.注射针与皮肤成60度角，向上、后、内进针
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听力题

Water is the most  79 of all the things we eat and   80 . Not many people 81  this but it is  82  . People can last their lives  83  food for a long time , yet two or three days without water can usually make people   84  .

Many people don’t understand how much water the human body   85  . If we don’t have 86  water, we’ll feel   87    and many of us will get  88  . So you know, how important water is to us all. And we should save water any time.
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