问题 单项选择题

在宽带综合业务数据网B-ISDN中,简化了网络功能的是______。

A.报文交换

B.虚电路交换

C.分组交换

D.ATM

答案

参考答案:D

解析: 在宽带综合业务数据网B-ISDN中,ATM简化了网络功能。其网络不参与任何数据链路层功能,将差错控制与流量控制工作交给终端去做,采用异步时分复用方式。

阅读理解

In the course of working my way through school, I took many jobs I would rather forget. But none of these jobs was as dreadful as my job in an apple plant. The work was hard; the pay was poor; and, most of all, the working conditions were terrible.

First of all, the job made huge demands on my strength. For then hours a night, I took boxes that rolled down a metal track and piled them onto a truck. Each box contained twelve heavy bottles of apple juice. I once figured out that I was lifting an average of twelve tons of apple juice every night.

I would not have minded the difficulty of the work so much if the pay had not been so poor. I was paid the lowest wage of that time—two dollars an hour. Because of the low pay, I felt eager to get as much as possible. I usually worked twelve hours a night but did not take home much more than $ 100 a week.

But even more than the low pay, what made me unhappy was the working conditions. During work I was limited to two ten-minute breaks and an unpaid half hour for lunch. Most of my time was spent outside loading trucks with those heavy boxes in near-zero-degree temperatures. The steel floors of the trucks were like ice, which made my feet feel like stone. And after the production line shut down at night and most people left, I had to spend two hours alone cleaning the floor.

I stayed on the job for five months, all the while hating the difficulty of the work, the poor money, and the conditions under which I worked. By the time I left, I was determined never to go back there again.

49. Why did the writer have to take many jobs at that time?

A. To pay for his schooling.

B. To save for his future.

C. To support his family

D. To gain some experience

50. The following facts describe the terrible working conditions of the plant EXCEPT ______.

A. loading boxes in the freezing cold                     B. having limited time for breaks

C. working and studying at the same time        D. getting no pay for lunch time

51. What is the subject discussed in the text?

A. The writer’s unhappy school life.               B. The writer’s eagerness to earn money.

C. The writer’s experience to earn money.      D. The writer’s hard work in an apple plant.

52. How is the text organized?

A. Topic—Argument—Explanation

B. Opinion—Discussion—Description

C. Main idea—Comparison—Supporting examples

D. Introduction—Supporting examples—Conclusion

单项选择题