Question

Five cloned pigs，whose organs are much less likely to be rejected(排斥) by a patient，have been born in the U．S.

More than 62,000 people in the U．S. alone are waiting to ____ donated hearts，lungs and so on.The number of human donors falls far short of ____.Pig organs are of a(n) ____ size to human organs，and some scientists hope they might be used to help meet the ____.But previous attempts to transplant pig tissue into humans have ____.

The five pigs ____ a gene that adds a sugar to the surface of pig cells.The sugar would ____ immune(免疫的) rejection of the tissue.“This advance provides a near­time ____ for overcoming the problem that there is not enough human organs for transplants，”says an expert.“This is the ____ gene for overcoming the ____ stage of rejection.”

____，scientists warn that much more work is necessary ____ organs from copies of the pigs could be transplanted into humans.Human genes will need to be added，to ____ rejection of the organ in the long term.There are also ____ that pig viruses could infect patients.

Cloning techniques were ____ to the production of the pigs.Genes can only be knocked out(去除) in a single cell.Cloning of these single cells then allowed the ____ of a whole animal in which the gene was knocked out in every cell.But the PPL researchers have ____ in knocking out only one copy of the gene.The team will now attempt to knock out both copies of the gene.

The team will also ____ tests to investigate whether a virus from the pigs could infect human cells.“Although a lot of the work is very ____，we’re still very far off being able to grow an organ，” says Julia，who is working on this project and quite ____ to creating similar knock­out pigs with researchers at the University of Missouri.

1.A.exchange  B．check

C．possess  D．receive

2.A.discussion  B．demand

C．doubt  D．distance

3.A.beneficial  B．identical

C．similar  D．certain

4.A.shortage  B．condition

C．satisfaction  D．argument

5.A.continued  B．failed

C．finished  D．paused

6.A.lack  B．include

C．make  D．change

7.A.leave  B．cause

C．block  D．destroy

8.A.supply  B．ambition

C．contribution  D．solution

9.A.only B．rare

C．key  D．safe

10.A.last  B．whole

C．next  D．early

11.A.However  B．Therefore

C．Besides  D．Finally

12.A.because  B．before

C．if  D．after

13.A.prevent B．ignore

C．judge  D．weaken

14.A.regrets  B．emotions

C．concerns  D．interests

15.A.simple  B．vital

C．unusual  D．basic

16.A.collection  B．application

C．reception  D．creation

17.A.delighted  B．succeeded

C．joined  D．believed

18.A.conduct  B．plan

C．design  D．study

19.A.perfect  B．strange

C．exciting  D．disappointing

20.A.opposed  B．used

C．devoted  D．suited

Answer

1.C

2.D

3.A

4.B

5.C

6.A

7.C

8.D

9.A

10.C

11.B

12.C

13.A

14.D

15.A

16.B

17.A

18.B

19.C

20.D

【解析】

1.

解析 由本段内容可知，应是等待接受器官的移植。

2.2】 B

解析 器官捐献不能满足人们的需求，demand符合语境。

3.3】 C

解析 根据上下文可知，克隆猪的器官可以被移植到人体内，它们的器官应该和人类的器官大小相似。

4.4】 A

解析 根据本段第二句“The number of human donors falls far short of ____.”可知，克隆猪的器官是为了弥补人类可移植器官的不足。

5.5】 B

解析 上一句提到科学家期望克隆猪的器官能够应用于人类器官移植领域，but表示转折，说明以前类似的试验失败了。

6.6】 A

解析 由下文“...a gene that adds a sugar to the surface of pig cells.The sugar would ____ immune(免疫的) rejection of the tissue.”可推测，这一基因会导致不好的结果，又根据“‘This advance provides...’”可知，这五只克隆猪没有这一基因，因此选lack。

7.7】 B

解析 根据上下文可知，这种糖分可能会使器官产生免疫排斥，cause符合语境。

8.8】 D

解析 根据后面overcoming the problem的提示，可知对人类可移植器官不足的问题提供了一个解决办法。

9.9】 C

解析 根据上文“...a gene that adds a sugar to the surface of pig cells.”可知，这一基因对克服器官排斥问题很关键，所以选key。

10.10】 D

解析 根据下一段第二句“Human genes will need to be added，to ____ rejection of the organ in the long term.”可知，对这一基因的处理只能解决器官排斥早期的一些问题。

11.11】 A

解析 根据下文“...scientists warn that much more work is necessary...”可知，本段内容与上一段意思是转折关系，所以用however。

12.12】 B

解析 根据下文“Human genes will need to be added...”可知，在克隆猪的器官可以移植到人体内之前，还有很多工作要做，所以用before。

13.3】 A

解析 根据上下文可知，科学家们的这些工作是为了防止器官排斥。

14.4】 C

解析 由句意可知，猪身上的病毒可能会感染病人，这是人们所担心的。

15.5】 B

解析 这五只猪是克隆动物，显而易见，克隆技术对繁育出这几只猪至关重要，vital符合语境。

16.6】 D

解析 基因的去除只有在单个细胞中才能进行，克隆这些单细胞然后再将其培育成一只完整的动物，这样动物身上的每个细胞中的这种基因就都被去除了，creation符合语境。

17.17】 B

解析 根据下文“The team will now attempt to knock out both copies of the gene.”可知，PPL researchers已经成功去除这种基因的一个副本。

18.8】 A

解析 句意为：这一团队还将进行试验研究克隆猪身上的细菌是否会感染人体。conduct tests进行试验。

19.9】 C

解析 although表示让步，根据主句“‘we’re still very far off being able to grow an organ，’”可知，exciting符合语境。

20.20】 C

解析 Julia致力于培育这种去除基因的克隆猪，devoted符合语境。