考博考试

【单选题】Questions 21—23 are based on a passage about cloning. You now have 15 seconds to read Questions 21—23. What has cloning bypassedA．The nuclear transfer.
B．The process takingDNA、
C．The normal reproductive process.
D．The creation of cells.

网考网参考答案：C
网考网解析：
[听力原文]21-23 What is cloning Cloning is the creation of cells or whole animals using DNA from a single "parent", bypassing the normal reproductive process, The clone has the same DNA as the parent. The most common process takes DNA from one cell and puts it in a hollowed-out egg. Chemicals and electricity are then used to encourage the new DNA to fuse with the egg and develop into an embryo. This technique is called nuclear transfer. The first cloned animal in human history was a sheep called Dolly. It is very important because it was the first mammal to be cloned using DNA taken from an ordinary adult cell. Previously, animals had only been cloned using embryo cells, which already have the potential to become a complete embryo in their own right. The big breakthrough with Dolly was to make a clone from an ordinary, adult cell. When it comes to the question of whether cloned animals are normal and healthy, the answer is YES. Dolly was, but scientists do not yet know whether this was the exception or the rule. Some early evidence suggests that clones may have health problems and that they may age prematurely. With the birth of Dolly, many people are worried that a human clone may be born soon. It’s possible in theory. But the technology of reproductive cloning is still in its very early stages and there is much that scientists do not understand. What’s more, human cloning is already banned by law in the United Kingdom. The former President of the United States Bill Clinton proposed banning research into producing human clones in the US for five years. Some measures have also been taken to establish international agreements banning live human clones. 克隆是个热门话题，有关克隆的文章无非谈沦两个问题，一是克隆技术，二是是否要克隆人类。把握这个主要方向，理解文章内容就比较容易了。此题问的是克隆超越了什么步骤，关键是读懂题目，如果不明白bypass只好抓住文章中的信息了。较大的干扰项是the nuclear transfer。 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>