问题 单项选择题

由于I/O设备工作速度太低,而且许多都是以字节方式工作的,所以即使采用中断技术,也还是要频繁地去中断主机CPU,扯了CPU的后腿。为此,操作系统采用了()技术。

A.假脱机

B.虚拟设备

C.缓冲

D.虚拟存储器

答案

参考答案:C

解析:可以用ORDER BY子句对查询结果进行排列,其中ASC表示升序,DESC表示降序。而GROUP BY子句是指对查询结果按某一列或多列值进行分组,值相等的为一组。

阅读理解

Having friends, and finding new friendships is an important developmental task for preteens and teens. While they have learned to play well with others during their childhood, developing independent friendships is a different thing. Preteens and teens will be allowed to use their own resources to decide whether to be someone’s friend or not, instead of being taught by their parents. Parents must give their teenagers some freedom in choosing who they want to hang out with.

You can help your teens to choose their friends, although it’s your teenagers who make the final decision. You can use teachable moments to talk about what makes a good friend. Here are some points to remember when you talk about friendships with your teenagers:

1) You are allowed to have many friends;

2) Honesty is important in a friendship;

3) Friends sometimes hurt each other, but they can say sorry and forgive(原谅);

4) Friends can influence each other, sometimes they will help you but sometimes they will hurt you, too.

5) Who you choose to be your friend is important, so choose wisely;

6) It takes many learned skills to make and keep a friendship, and it also takes many skills to end a friendship;

7) It is okay and even helpful to make friends with the opposite gender(异性);

8) It takes time to make a good friend, but it is worth the effort;

9) Spending time together will help you get to know your friends well and you will feel comfortable sharing feelings;

10) A good friendship will make you feel good about yourself.

小题1:What should their parents do when teenagers make friends?

A.Do nothing but give them all the freedom.

B.Talk with them and give some help.

C.Decide and choose friends for them.

D.Stop them from making friends with opposite gender.小题2:Which point is about how to end a friendship?

A.Point 3.

B.Point 4.

C.Point 5.

D.Point 6.小题3:Which of the following is NOT needed in making friends?

A.Honesty.

B.Effort.

C.Lies.

D.Skills.小题4:Who is the passage mainly written for?

A.Teachers.

B.Parents.

C.Preteens.

D.Teens.小题5:Which of the following statement is true?

A.Friends never hurt each other.

B.There is no need to forgive friends.

C.Teenagers are allowed to have many friends.

D.Girls should never make friends with boys.

单项选择题