A
Chinese scientists recently have produced two monkeys with the same gene, Zhong Zhong and Hua Hua, using the same technique that gave to Dolly the sheep. These monkeys are not actually the first primates(灵长类) to be cloned. Another one named Tetra was produced in the late 1990s by embryo(胚胎) splitting, the division of an early－stage embryo into two or four separate cells to make clones. By contrast, they were each made by replacing an egg cell nucleus(细胞核) with DNA from a differentiated body cell. This Dolly method, known as somatic cell nuclear transfer(SCNT), can create more clones and allows researchers greater control over the edits they make to the DNA.
Success came from adopting several new techniques. These included a new type of microscopy to better view the cells during handling or using several materials that encourage cell reprogramming, which hadn't been tried before on primates. Still, the research process proved difficult, and many attempts by the team failed. Just two healthy baby monkeys born from more than 60 tested mothers. This leads to many researchers' pouring cold water on the idea that the team's results bring scientists closer to cloning humans. They thought this work is not a stepping stone to establishing methods for obtaining live born human clones. Instead, this clearly remains a very foolish thing to attempt, it would be far too inefficient, far too unsafe, and it is also pointless.
But the scientists involved emphasize that this is not their goal. There is now no barrier for cloning primate species. Thus cloning humans is closer to reality. However, their research purpose is entirely for producing non－human primate models for human diseases; they absolutely have no intention, and the society will not permit this work to be extended to humans. Despite limitations, they treat this breakthrough as a novel model system for scientists studying human biology and disease.
语篇导读 中国科学家利用SCNT技术克隆出了两只猴子，文章介绍了相关信息并讨论了这种克隆实验的影响。
1．What do we know about the technology called SCNT?
A．It created the first two primates.
B．It may contribute to editing the DNA.
C．It can divide an early－stage embryo into several cells.
D．It produced two cloned monkeys with different genes.
解析 B 细节理解题。根据第一段最后一句可知，SCNT可以帮助研究者在编辑DNA时更加有效控制，即可能有助于编辑DNA，故选B项。
2．What does the author mean by saying “pouring cold water on the idea” in Paragraph 2?
A．Keeping a hot topic of it.
B．Having a low opinion of it.
C．Attaching no importance to it.
D．Adding supportive evidence to it.
解析 B 词义猜测题。根据画线处上一句可知，研究的过程比较困难，多次尝试均以失败告终，所以许多科学家对这一实验理念并不看好。have a low opinion of不看好……，故选B项。
3．What is the scientists' purpose to clone these monkeys?
A．To help with the study of human diseases.
B．To serve as a stepping stone to their reputation.
C．To prepare for their research on human cloning.
D．To raise money for holding an exhibition of novels.
解析 A 细节理解题。根据第三段第四句可知，科学家们克隆这些猴子的目的是帮助研究人类疾病，故选A项。
4．What can we infer from the passage?
A．New techniques seem to be pointless.
B．Cloning humans is already on its way.
C．Society won't agree to clone another monkey.
D．Cloning monkeys has made contributions to certain scientific areas.
解析 D 推理判断题。根据第三段最后一句可知，成功克隆猴子为研究人类生物学和疾病提供了新的范例；由此可推知，成功克隆猴子已经为某些科学领域作出了贡献，故选D项。
