Question

With their furry round heads and big black eyes, Zhongzhong and Huahua look just the same as any other monkey. But they happen to be the world’s first cloned (克隆的) monkeys.

Years ago, scientists used cloning techniques to produce Dolly, the world’s first cloned mammal (哺乳动物).They now used the same technique to produce the monkeys in China.

In animal cloning, animals are produced in a lab by using DNA that is taken from the cells (细胞) of a naturally-born animal. To clone Zhongzhong and Huahua, scientists from the Chinese Academy of Sciences (CAS.中国科学院) first removed the nucleus (细胞核) from a monkey’s egg cell (卵细胞). They then put another nucleus taken from the monkey’s body cells into the egg cell. The newly-formed egg was put into the womb (子宫) of a female monkey. Finally, Zhongzhong and Huahua were born.

The cloning process is hard, especially removing nucleus. It needs to be done in a fast and precise (精确的) way. The faster you do it, the less damage is done to the egg, according to CAS. Scientist Liu Zhen spent three years practicing removing the nucleus.

Unlike common monkeys, cloned monkeys have the same DNA as each other. When doing experiments on them, scientists can easily know that certain results are caused by different treatments, rather than different genes.

According to Sun Qiang from CAS, most drug trials (药物试验) are done on lab mice. However, drugs that work on mice might not work on humans. The two species are very different.

“Monkeys and humans are much closely related and testing on monkeys is supposed to be as effective (有效的) as testing on humans,” Sun added.

1.Zhongzhong and Huahua are ______.

A. naturally-born monkeys

B. the world’s first cloned mammals

C. the world’s first cloned monkeys

D. twin sheep that were born by Dolly

2.What do we know about the two monkeys?

A. They look different from other monkeys.

B. They have the same DNA.

C. Their body cells don’t have any nucleus.

D. They can live for only three years.

3.What can we learn from Paragraph 4?

A. Removing the nucleus is difficult.

B. The cloning process is very safe.

C. It took three years to remove the nucleus.

D. It is impossible to clone other animals.

4.Why do scientists want to do drug tests on monkeys?

A. Because it’s easier to use them for tests.

B. Because there are not enough mice.

C. Because drugs work well on monkeys.

D. Because monkeys are similar to humans.

Answer

1. C

2. B

3. A

4. D

【解析】

本文为说明文。经过艰难的研究攻关，中国科学院取得重大突破，在国际上首次实现了非人灵长类动物的体细胞克隆。中中和华华成为世界上首对克隆猴。

1.细节理解题。由第一段的“Zhongzhong and Huahua look just the same as any other monkey. But they happen to be the world's first cloned monkeys”可知，中中和华华是世界上首对克隆猴。分析选项可知C符合题意，故选C项。

2.细节理解题。由倒数第三段第一句“Unlike common monkeys, cloned monkeys have the same DNA as each other”可知，这对克隆猴DNA彼此相同。分析选项可知B符合题意，故选B。

3.细节理解题。由第四段的“The cloning process is hard, especially removing nucleus…. The faster you do it, the less damage is done to the egg, according to CAS. Scientist Liu Zhen spent three years practicing removing the nucleus”可知，“克隆过程很难，尤其是移除细胞核.它需要以快速而精确的方式完成。根据中科院的说法，你做得越快，对鸡蛋的伤害就越小。科学家刘震花了三年时间练习移除原子”，由此可知A项正确，故选A。

4.推理判断题。最后一段提到了“ Monkeys and humans are much closely related and testing on monkeys is supposed to be as effective (有效的) as testing on humans”由此可知“猴子和人类比较接近，对猴子的测试应该和对人类的测试一样有效”，所以科学家想用猴子做药物实验。分析选项可知D项符合题意，故选D。