脱轨事故可能由（）造成。A.严重啃轨 B.吊物太轻 C.起升速度过快 D.起升速度过

已知定义在R上的奇函数f(x)，当x＞0时，f(x)=x-1；那么当x=0时，f(x)=（    ）；当x＜0时，f(x)=（    ）。

禁止从英国、法国等国家进口牛及牛制品是为了防止“疯牛病”即( )进入我国。

A．牛海绵状脑病

B．牛肺疫

C．兰舌病

D．以上都不对

8255A的端口A工作在方式2时，如果端口B工作在方式1，则固定用作端EIB的联络信号的端口的信号是( )。

A．PC2～PC0

B．PC2～PC4

C．PC7～PC5

D．PC3～PCI

阅读理解(满分40分)

第一节（共15小题年每小题2分，满分30分）

请阅读下列短文，从每题所给的四个选项（A、B、C、D）中，选出最佳答案，并在答题卡上将该选项的标号涂黑。

A

When I was a child, I often dreamed of the time when I could leave home and escape to the city. We lived on a farm, in the winter especially, we wear quite out off from the outside world. As soon as I left school, I packed my bags and moved to the capital.

However, I soon discovered that one big disadvantage is money. It costs so much to go out, not to mention basics like food and housing. Another disadvantage is pollution. I suffer from asthma(哮喘), and  the air is so bad that I am afraid to go outside. Then there is the problem of traveling round. Although I have a car, I seldom use it became of the traffic jams. One choice is to go by bicycle, but that can be quite dangerous.

Of course there are advantages. First, there is so much to do in the city, whatever you tastes in culture or entertainment(娱乐活动). Besides, there are wonderful jobs and greater chances of moving to a more important job or position. Finally, if you like shopping, the variety of goods is very surprising --- and , what is more, shops are often only a short walk away.

Is life better then, in the city? Perhaps it is , when you are in your teens(十几岁)or twenties. However, as you get older, and especially if you have small children, the peace of the countryside may seem preferable. I certainly hope to move back there soon.

61. What was the writer always thinking about when he was a child?

A. Staying on the farm.                B. Moving to the countryside.

C. Leaving home for the city.           D. Running away from the school.

62. Which of the following is true about the writer?

A. He is very old now.                 B. He is in good health.

C. He prefers driving a car.             D. He lives in the city now.

63. In the passage, the writer tries to __________.

A. express his opinions about way of life      B. describe his life in the countryside

C. an interest in the outside world            D. persuade the reader to live in the city

64. How is the passage mainly developed?

A. By inferring.         B. By comparing.       

C. By listing examples.   D. By giving explanations.

锅炉点火过程应注意什么问题？