问题 填空题

m增大2倍。()

(1)的分母增大2,要保持分数值不变;

(2)

的分母变为原来的2倍,要保持分数值不变.

答案

参考答案:E

解析:

条件(1)、(2)其实分母都变成了4,即分母变为原来的2倍了,所以要保持值不变,则分子也应变为2m,即增大1倍,均不充分.

阅读理解

     Life in the twenty-first century will be very different from life today. Between then and now many

changes will take place, but what will the changes be?

     The population is growing fast. There will be many people in the world and most of them will live

longer than people live now.

     Computers will be much smaller and more useful, and there will be at least one in every home.

And computer studies will be one of the important subjects in schools then.

     People will work fewer hours than they do now and they will have more free time for sports,

watching TV and travelling. Travelling will be much easier and cheaper. And many more people will

go to other countries for holidays.

     There will be changes in our food, too. Maybe no one will eat meat every day, instead they eat

more fruit and vegetables. Maybe people will be healthier.

     Work in the future will be different, too. Dangerous and hard work can be done by robots.

Because of this, many people will not have enough work to do. This will be a problem.

根据短文内容,选择正确答案。

1.There will be _________ in the future.

A. small population

B. few changes

C. more people

D. few people

2.In the future the computer will be _________.

A. much bigger and few people will use it

B. much smaller and more useful

C. smaller and not many people will use it

D. bigger and a lot of people will use it

3.In the future more people _________.

A. will go to other countries for holidays

B. will study at school

C. will go earlier

D. will work for many hours

4.People will prefer _________ to _________ in the future.

A. fruit and vegetables; meat

B. meat; fruit and vegetables

C. fruit and meat; vegetables

D. meat and vegetables; fruit

5. The robots will _________ in the future.

A. do the dangerous work

B. do all the work

C. do only housework

D. do the easy work for people

单项选择题