问题 问答题 简答题

你认为中性突变进化学说是对达尔文学说的否定吗?为什么?

答案

参考答案:

否。因为达尔文注意到了变异的有害性和有利性,而中性突变进化学说注意到的是既无利也无害的所谓中性突变,应该说是从不同角度,不同层次看问题的结果,使达尔文学说得到了补充和发展。且中性说是始终以分子水平的结构来提问题的,而达尔文学说是从表型水平来说的,二者并不相矛盾。

阅读理解

阅读理解。

     In the 13th century, the famous Indian traveller, Marco Polo, travelled a long way to China. He saw

many wonderful things. One of the things he discovered was that Chinese used paper money. In western

countries, people did not use paper money until the 15th century. However, people in China began to

use paper money in the 7th century.

    A Chinese man called Cai Lun invented paper almost 2,000 years ago. He made it from wood. He

took the wood from trees and made it into paper. He then put these pieces of paper together and made

them into a book.

    Now paper still comes from trees. We use a lot of paper every day. If we keep on wasting so much

paper, there will not be any trees left on the earth. If there are no trees, there will be no paper. Every day, people throw away about 2,800 tons of paper in our city. It takes 17 trees to make one ton of paper.

This means that we are cutting nearly 48,000 trees every day. Since it takes more than 10 years for a tree

to grow, we must start using less paper now. If we don’t, we will not have enough time to grow more trees to take the place of those we use for paper.

     So how can we save paper? We can use both sides of every piece of paper, especially when we are

making notes. We can also use cotton handkerchiefs(手帕) and paper ones. When we go shopping, we

can use fewer paper bags. If the shop assistant does give us a paper bag, we can save it and refuse(拒绝)

it later.

Everyone can help to save paper. If we all think carefully, we can help protect trees. But we should do it

now, before it is too late.

1. When he was in China, Marco Polo ________ .

A. discovered Cai Lun invented paper

B. learned to make paper

C. saw many wonderful things

D. read a lot of books

2. People in western countries first used paper money in the ________ century.

A. 17th

B. 15th

C. 13th

D. 7th

3. About ________ tons of paper are thrown away every day in our city.

A. 1,700

B. 2,000

C. 2,800

D. 48,000

4. Which of the following is the way of saving paper?

A. To use both sides of every piece of paper.

B. To use the paper bags from shops more than once.

C. To use cotton handkerchiefs and paper ones.

D. All of the above.

5. Which is the best title(题目)of the passage?

A. Saving paper.

B. The history of paper.

C. Cotton handkerchiefs back again.

D. Cai Lun, the great inventor.

单项选择题 A2型题