根据基数效用理论，边际效用与总效用的关系是怎样的？

阅读短文，选择正确答案。

     Perhaps you have heard a lot about the Internet, but what is it?

     The Internet is many different networks (网络) around the world. A network is a group of computers put

together. These networks joined together are called the Internet.

     Maybe that doesn't sound interesting. But when we've joined the Internet, there are lots and lots of things

we can do. We can have a lot of interest on the World Wide Web(www). We can use the Internet instead of a

library to find all kinds of information for our homework. We can find information about our favourite sports or

film stars and do shopping on the Internet. We can also send messages to other people by e-mail. It is much

cheaper and quicker than calling our friends or sending a letter.

     With the help of the Internet, the world is becoming smaller and smaller. People can now work at home with

a computer in front, getting and sending the information they need.

     They can buy or sell the things they want by the Internet. But do you know 98% of the information is in

English? So what will English be like tomorrow?

1. The passage is mainly about _______.[ ]

A. the Internet

B. information

C. computers

D. e-mail

2. The quickest and cheapest way for people to send messages to their friends is ________.[ ]

A. by post

B. by e-mail

C. by telephone

D. by TV

3. The Internet can not be used to _______.[ ]

A. find information for our homework

B. get some information about our favourite sports stars

C. do some shopping

D. do our housework

4. Which of the following is NOT true? [ ]

A. The Internet is a big computer.

B. The Internet is lots of computer networks.

C. The Internet is very helpful.

D. People can work at home with the help of the Internet.

5. What does the writer try to tell us with the last two sentences? [ ]

A. The Internet is more and more popular.

B. All the information is in English.

C. English is important in using the Internet.

D. Every computer must join the Internet.

刀耕火种的农业需要烧掉数亩森林，把植物的灰烬留在地里为以后三四年的粮食丰收准备丰富的肥料。然而，此后土地将逐渐失去养分，以至于无法继续耕种，因此，又需要通过刀耕火种的方法来开垦新的土地，一切又从头开始。由于热带大部分农业使用这种方法，因此，在这一地带的森林将最终被永久地根除。
上述论证以下面哪一项为假设

A．热带森林用刀耕火种的方法修整过后不能很好地再生以恢复原貌。
B．其他农艺方法不像刀耕火种方法这样对热带地区的环境造成破坏。
C．热带森林本质上非常缺乏这一地区所固有的农作物的生长所需要的养分。
D．刀耕火种的方法特别适合于热带地区的农业。
E．刀耕火种的方法在第一年能比任何其他方法取得更大的收获。

手机报作为中国移动自有业务，宣传的客服电话统一为（）。

A、125901860

B、10086

C、010-66426650

D、010-59310899

图书物流，即图书商品实体形态的流通，包括商品实体在流通过程中所形成的（）和空间上的运动。

2007年纳入国家税务总局重点税源监控的标准是（）。

A、年主营收入1亿元以指示

B、年主营收入5000万元以上

C、年入库“两税”500万元以上

D、年入库企业所得税500万元以上