问题 选择题

美国等国家联合发射的航天器,将我国研制的磁谱仪带入太空,其目的是探索“反物质”.“反物质”的主要特征是电子带正电荷,质子带负电荷.以下表示“反物质”酸碱中和反应的通式是(  )

A.H-+OH+=H2O

B.H++OH-=H2O

C.H++OH+=H2O

D.H-+OH-=H2O

答案

中和反应的通式是氢离子与氢氧根离子结合成水,所以结合氢离子实际上是质子,反物质带负电,氢氧根离子多余一个电子带正电,从而可判断A正确.

故选A

阅读理解

阅读理解。

    New rules and behavior standards (行为规范) for middle school students came out in March. Middle

school is going to use a new way to decide who the top students are. The best students won't only have

high marks. They will also be kids who don't dye (染) their hair,smoke or drink. The following are some

of the new rules.

    Tell the truth. Have you ever copied someone else's work on an exam? Don't do it again! That's not

something an honest student should do. If you have played computer games for two hours in your room,

don't tell your parents you have done homework.

     Do more at school. Good students love animals and care for other people. April is Bird-Loving Month

in our country. Is your school doing anything to celebrate?You should join! That way, you can learn more

about animals and how to protect them. When more people work together, it makes it more fun for

everyone. Have you ever quarreled with your teammates when your basketball team lost? Only working

together can make your team stronger. Be friendly to the people you are with. Try to think of others, not

only yourself.

     Be open to new ideas. Have you ever thought that people could live on the moon? Perhaps you'll discover

Earth II someday. Don't look down on new ideas. Everyone's ideas are important. You should welcome

them, because new ideas make life better for everyone. Protect yourself. Has someone ever taken money

from one of your classmates? Don't let it happen to you. If you have to go home late,you should let your

parents know. Use the Internet carefully. The Internet can be very useful for your studies. But some things

on the Internet aren't for kids, so try to look at Web pages that are good for you. You can use the Web for

fun or homework. Can't you find any good Web sites for children? Here are some:

      http://kids.eastday.com/     http://www.chinakids.net.com/   http://www.cycnet.com

1. The school new rules will help kids by telling them ___. [ ]

A. how they can study well

B. how to learn English

C. what is right and what is wrong

D. how they can protect themselves

2. According to the passage,which of the following is NOT true? [ ]

A. Take care of yourself when you are out.

B. Tell the truth, even when you are wrong.

C. Keep some animals to protect them.

D. Use the Internet, but keep away from bad things.

3. The main idea of the third paragraph is about ___. [ ]

A. making the team stronger

B. working together with others

C. being a good friend to others

D. getting on well with others

4. Good Web sites for children can ___. [ ]

A. be a waste of time

B. help them with their studies

C. do homework for them

D. make life easier

5. The passage tells us how to ___. [ ]

A. be top students

B. do more at school

C. care for others

D. use the Internet

单项选择题