发生在煤矿地面以下的火灾叫矿井火灾

阅读理解。

     We each have a memory. That's why we can still remember things after a long time. Some people

have very good memories and they  can easily  learn many  things by heart, but some people can only

remember things when they say or do them again and again. Many of the great men of the world have

got surprising memories.

     A good memory is a great help in learning a language. Everybody learns his mother language when

he is a small child. He hears the sounds, remembers them and  then he learns to speak. Some children

are living with their parents in foreign countries. They can learn two languages as easily as one because

they hear, remember and speak two languages every day. In school it is not so easy to learn a foreign

language because the pupils have so little time for it, and they are busy with other subjects, too.

     But your memory will become better and better when you do more and more exercises.

1.Some people can easily learn many things by heart because .

A．they always sleep very well

B．they often eat good food

C．they read a lot of books

D．they have very good memories

2.Everybody learns his mother language .

A．at the age of six

B．when he is a small child

C．after he goes to school

D．when he can read and write

3.Before a child can speak, he must .

A．read and write

B．make sentences

C．hear and remember the sounds

D．think hard

4.In school the pupils can't learn a foreign language well because .

A．they have no good memories

B．they have no recorders

C．they have too much time for it

D．they are busy with other subjects

5.Your memory will become better and better .

A．if you have plenty of good food

B．if you do more and more exercises

C．if you do morning exercises every day

D．if you get up early

报关现场业务一般由（）环节构成。

A.进出口申报

B.配合查验

C.提供担保

D.提取或装运货物

电机车同一轴两车轮直径不超过（）mm，前后轮对直径不超过（）mm。

A.2,4

B.3,4

C.4,4

2000年，中国财政大幅度增加社会保障支出，仅中央财政就安排养老、失业、下岗职工基本生活保障和城镇居民最低生活保障等社会保障支出478亿元，比1999年增长86%。到2000年底，全国有10408万职工参加失业保险，日平均领取失业保险金人数为188万人；有10447万职工和3170万离退休人员参加了基本养老保险；有4300万职工参加了基本医疗保险。

参加基本养老保险的有多少人（）

A．10408万

B．10447万

C．3170万

D．13617万

试述三角木和掩木的加固作用，规格及使用要求？