如图所示，斜面长s=4m，高h=2m，用平行于斜面向上的7.5N的拉力将10N重的物体从斜面底端匀速拉到斜面顶端，则（　　）

解答题

油桶制造厂的某车间主要负责生产制造油桶用的圆形铁片和长方形铁片，该车间有工人42人，每个工人平均每小时可以生产圆形铁片120片或者长方形铁片80片．如图，一个油桶由两个圆形铁片和一个长方形铁片相配套．生产圆形铁片和长方形铁片的工人各为多少人时，才能使生产的铁片恰好配套？

1953年我国开始实行粮食的计划收购与计划供应政策，统购价格由中央规定，对城市人民和农村缺粮人民实行粮食计划供应，严禁私商自行经营粮食。这一政策的制定（    ）

 I was flying to New York at night. Suddenly, a storm broke and the plane began to be tossed(颠簸)around.

 When I looked1  the plane, I could see that nearly all the passengers were worried and afraid. The future seemed terrible and many were   2   if they would make it through the storm.

 Then , I  3 saw a little girl. It seemed that the storm meant  4 to her. She sat on her seat reading a book. Sometimes she closed her eyes, then she would read again, with no  5 or fear in her eyes. When the other passengers were scared(惊恐的) half to death, that child was completely calm and  6  . I couldn't believe my eyes.

 When the plane finally reached New York, I was not surprised to  7  that all the passengers were hurrying to come out. I stopped and spoke to the girl whom I had  8  for such a long time. I asked 9 she had not been afraid.

 The child replied, “My daddy is the  10   , and he is taking me home.”