问题 选择题

伽利略曾设计如图所示的一个实验,将摆球拉至M点放开,摆球会达到同一水平高度上的N点。如果在E或F处钉上钉子,摆球将沿不同的圆弧达到同一高度的对应点;反过来,如果让摆球从这些点下落,它同样会达到原水平高度上的M点,这个实验可以说明,物体由静止开始沿不同倾角的光滑斜面(或弧线)下滑时,其末速度的大小

[      ]

A.只与斜面的倾角有关

B.只与斜面的长度有关

C.只与下滑的高度有关

D.只与物体的质量有关

答案

C

阅读理解

阅读理解。

     With July comes the exam. When the exams finish, the summer vacation begins. Boys and girls have

two months to rest. The summer vacation is the best part of the year for most children. The weather is

usually good. They can swim, go to summer camp or visit other places with their parents.

     Of course, the beaches are good places to relax. Some children are lucky to live near the sea. They

can enjoy the sea at anytime. But for the children who live far from the sea, they go to the beaches for

one or two weeks with their parents.

     Why do children like spending their summer vacation on the beaches? It is because they like the sand,

the sun, the cool wind and the salt water. There are lots of new things to see, nice things to eat, and

exciting things to do.

1. School children usually have examinations _____.        

A. in July                   

B. before July          

C. after July                 

D. by July

2. How long is the summer vacation?          

A. Two weeks.          

B. Two months.          

C. Three months.          

D. One or two weeks.

3. Why do children like summer vacation?         

A. Because the weather is good.           

B. Because it is long.           

C. Because they have lots of activities and the weather is good.           

D. Because they can go to the beaches.

4. Children who live near the beaches can enjoy the sea _____.         

A. at anytime they want         

B. for one or two weeks          

C. two months          

D. one month

5. Which of the following is NOT true?         

A. Children like going to the beaches only because they can see lots of new things.          

B. Most parents can take their children to the beaches and they can enjoy the sea at any  time.          

C. Children like summer vacation best.          

D. Children can swim and enjoy the sand, wind, and water on the beaches.

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