问题 单项选择题

让作业不会同时调用的子模块使用相同的内存区,使系统有限的内存资源得到有效的利用,这种技术称为( )。

A.交换技术

B.覆盖技术

C.物理扩充

D.虚拟扩充技术

答案

参考答案:B

解析:[分析] 由于CPU在某一时刻只能执行一条指令,所以一个作业不需要一开始就全装入内存,于是将作业的常驻部分装入内存,而让那些不会同时执行的部分共享同一块内存区,后调入共享区的内容覆盖前面调入的内容,这就是内存的覆盖技术。

阅读理解

阅读理解。

     根据短文内容,从短文后的选项中选出能填入空白处的最佳选项,选项中有两项为多余项。

     Do you know how to be street smart? Being street smart means knowing how to keep yourself safe

from strangers when you're alone or with other kids.    1  

     Most strangers aren't dangerous and wouldn't do anything to hurt kids. Unfortunately, though, some

strangers can be dangerous, and it's impossible to tell who's OK and who's not. __2_  That's why it's

important to follow these safety rules all the time:

     Make your whereabouts known.

     The adults who's taking care of you needs to know where you are and when you'll be coming home.

        3  

     It's more fun and safer to do things with friends. Traveling with a friend whenever you can is a good

idea, and traveling with a group of kids is even better.

        4  

     Safe spots are places where you can stop if you need help. Like the houses of kids you know, the

houses of your parents' friends, police stations, libraries, and fire departments. When you're walking or

riding your bike, make a mental note of the safe spots along your route. That way, you'll know where

they are in case you ever need one.

        5  

     You're probably been told lots of times that you should not yell and keep quiet. But when you think

you might be in danger, it's the perfect time to be noisy! If a stranger approaches you, follows you or tries

to grab you, yell as loudly as you can and try to get away. People in the area will hear what's going on and help you, so make plenty of noise.

A. Stick with a friend.

B. Pick out safe spots.

C. It helps you stay safe.

D. Shout "help" when necessary.

E. Go to school with your friends.

F. Make a lot of noise if you are scared.

G. A dangerous person doesn't necessarily look scary.

填空题