问题 单项选择题

中断向量是 ( )

A.外设提出中断

B.由硬件形成向量中断地址,再由向量地址找到中断服务程序入口地址

C.由硬件形成中断服务程序入口地址

D.以上说法均错

答案

参考答案:B

解析: 中断向量就是中断服务程序的入口地址,每一个中断服务程序都有一个唯一确定的入口地址,即中断向量。

阅读理解

阅读理解。

     In most parts of the world, many students help their schools make less pollution (污染). They join

"environment clubs (环境俱乐部)". In an environment club, people work together to make our

environment clean.

     Here are some things students often do.

     No-garbage (垃圾) lunches. How much do you throw away after lunch? Environment clubs ask

students to bring their lunches in bags that can be used again. Every week they will choose the classes

that make the least garbage and report them to the whole school!

     No-car day. On a no-car day, nobody comes to school in a car-not the students and not the

teachers! Cars give pollution to our air, so remember:

     Walk, jump, bike or run.

     Use your legs! It's lots of fun!

     Turn off the water! Did you know that some toilets can waste(浪费) twenty to forty m3 of water an

hour? In a year, that would fill a small river! In environment clubs, students mend those broken toilets.

     We love our environment. Let's work together to make it clean.

1. Environment clubs ask students         .

A. to run to school every day            

B. to take exercise every day

C. not to forget to take cars              

D. not to throw away lunch bags

2. From the passage we know the students usually have lunch         .

A. at school          

B. in shops        

C. in clubs        

D. at home

3. On a no-car day,          will take a car to school.

A. both students and teachers              

B. only students

C. neither students nor teachers            

D. only teachers

4. After students mend toilets, they save          .

A. a smaller river      

B. a club      

C. a lot of water      

D. a toilet

5. The writer wrote the passage to ask students to          .

A. clean schools    

B. make less pollution      

C. join clubs      

D. help teachers

单项选择题 A3/A4型题