Question

    They make a guest appearance in at least half of the articles on Medical News Today. They are responsible for many of the biggest breakthroughs in medicine. However, the humble lab mice also shoulder much of the blame when the failure of drugs to translate from animal models to humans keeps worrying the whole of medical research. Should scientists abandon lab mice altogether?

Mice were introduced into the lab back in the 1920s. An ambitious young American geneticist Clarence Cook Little strongly believed that cancer was an inheritable (有遗传性的) disease, and that mice were the ideal subjects for his experiments.

Other animals were, and still are, used to study disease. Cats and dogs are popular, as well as chimpanzees. Of course, ethical (伦理的) considerations get more complicated the further up the food chain you go. And mice are in sufficient numbers for researchers to conduct thousands of trials. Add to that the problem of cost: A standard lab mouse costs about $20---far cheaper than a healthy cat or dog. So their importance in scientific research has become well-established.

We share more than 97 percent of our working DNA with mice, a consequence of a shared ancestor 75 million years ago. This similarity has been both a blessing and a curse. While we share many basic biological processes, it is the three percent of the genes which set us apart from mice that can have a big influence on how our bodies work.

Mice may not always be the perfect model for understanding our own bodies, but they do hold real value to researchers. Their usefulness will only increase as scientists work out better ways to modify (修改) their genes to compensate for their shortcomings. The difficult part of the issue may be that researchers need to be more critical as they evaluate the type of model that is best for their experiment.

In the end, the story of scientists’ relationship with lab mice will possibly be one of gradual advances to improve an imperfect system. This is exactly how most scientific research progresses — by critically examining what we know to expand our knowledge of what we do not.

1.What does the underlined word “they” in the first paragraph refer to?

A.American geneticists B.cats and dogs

C.lab mice D.breakthroughs in medicine

2.Paragraph 4 mainly answers the question “________?”

A.Why do drugs that work in mice fail when tried in humans

B.Why are mice the ideal subjects for medical research

C.Why do we and mice share more than 97% of our working DNA

D.How can we understand our own bodies by studying lab mice

3.Which of the following statements is TRUE according to the passage?

A.Mice are in sufficient numbers because they are at the lower part of the food chain.

B.Many scientist are considering stopping the use of lab mice.

C.More genetically modified mice will be used in medical research in the near future.

D.It will become easier for researchers to choose the proper type of lab mice.

4.What is the author’s attitude to the use of lab mice?

A.Disappointed B.Supportive

C.Indifferent D.disapproving

Answer

1.C

2.A

3.C

4.B

【解析】

这是一篇说明文。文章主要讲述了由于3%的基因使我们有别于老鼠，从而使得在老鼠身上有效的药物在人类身上试验时却失败。老鼠也许并不总是理解我们身体的完美模型，但它们确实对研究人员有真正的价值。科学家找出更好的方法来修改他们的基因，以弥补他们的缺点其效用只会增加。从而得出结论：科学家与实验室老鼠之间的关系可能是一个逐步改进不完善系统的故事。

1.词义猜测题。结合后文“However, the humble lab mice also shoulder much of the blame when the failure of drugs to translate from animal models to humans keeps worrying the whole of medical research.”然而，当药物不能从动物模型转化到人类身上的时候，整个医学研究都在担忧，实验室里不起眼的老鼠也要承担大部分责任。句中有also，可推知，应与前文“they”所在句为递进关系，可推知两句主语相同。因此句中主语“the humble lab mice”应与前文人称代词“they”为相同含义。故选C项。

2.推理判断题。根据第四段末尾内容“While we share many basic biological processes, it is the three percent of the genes which set us apart from mice that can have a big influence on how our bodies work.”可知虽然我们有许多共同的基本生物学过程，但正是这3%的基因使我们有别于老鼠，对我们身体的运作方式产生了巨大的影响，从而使得在老鼠身上有效的药物在人类身上试验时却失败了。因此可以推知，第四段主要回答了“为什么在老鼠身上有效的药物在人类身上试验时却失败了？”这个问题。故选A项。

3.推理判断题。根据文章第段内容“Their usefulness will only increase as scientists work out better ways to modify their genes to compensate for their shortcomings.”可知当科学家们找到更好的方法来修改老鼠的基因以弥补他们的缺陷时，老鼠的用处只会增加，因此可以推知，在未来，将会有更多的被修改基因的实验老鼠。故选C项。

4.推理判断题。根据文章末段内容“In the end, the story of scientists’ relationship with lab mice will possibly be one of gradual advances to improve an imperfect system. This is exactly how most scientific research progresses — by critically examining what we know to expand our knowledge of what we do not.”可知在作者看来科学家与实验室老鼠的关系可能是一个逐步改进不完善的系统的故事，而这正是大多数科学研究的进展——通过批判性地检查我们所知道的来扩展我们所不知道的知识。因此可以推知作者对于实验室老鼠在科学研究方面的评价是正面积极的。故选B项。