问题 单项选择题

下列各项中,促使泥石流发生的决定性因素为( )。

A.地势陡峻、纵坡降较大的山区
B.短时间内有大量水的来源
C.地质构造复杂岩石破碎
D.崩塌滑坡灾害多

答案

参考答案:B

解析: 泥石流是含有大量泥砂石块等固体松散物质的有很大破坏力的洪流。其形成必须具备丰富的松散固体物质、足够的突发性水源和陡峻的地形3个基本条件。其中,水不仅是泥石流的组成部分,也是固体物质的搬运介质,泥石流的形成必须有强烈的地表径流,这是爆发泥石流的动力条件,也是决定性因素。

阅读理解

Read and choose. (阅读短文,选择正确答案)                                      

                                                      A Friendly American Family

     The Smiths are Americans. They are now in Beijing.  This is their first visit to China. They are going

to stay in China for two months. They want to visit some cities and villages(村庄). They hope to learn

some Chinese, too.

     Mr Smith is a doctor.  He will visit a hospital in Shanghai. Mrs Smith is a school teacher.  She is

going to some schools in cities and villages. Their daughter is a primary school student. She wants to

meet some Chinese students.

     They are going to take a lot of pictures in China.  When they are back in America, they will show

the pictures to their friends. They want the American people to know more about China.

1. Where are the Smiths from?              

A. Canada.            

B. America.            

C.  China.

2. What do they want to do in China?               

A. Teach English.    

B. Play games.          

C. Visit some cities and villages.

3. Where does Mrs Smith work?                      

A. In a restaurant.    

B. In a hospital.          

C. In a school.

4. Who wants to meet the Chinese students?              

A. Mr Smith's daughter.

B. Mr and Mrs Smith.

C. Mr Smith and her daughter.

5. What do they want to do when they are back home?              

A. Show the pictures of China to their friends.

B. Have a good rest.

C. Clean their house.

判断题