问题 单项选择题

根据短文回答48—51题:科学家创造出一台DNA计算机,并让它解决一些较复杂的运算问题,他们认为,这台寿命很短的计算机虽然不实用,但它正走出科幻世界,成为一种现实的DNA计算技术。史密斯教授说:“这是一种非自动化的计算机——就像算盘那样,但我们相信它可以像常规计算机一样实现自动化。”常规计算机的技术正在迅速接近微型化的极限,科学家梦想对DNA及RNA的用于保存复杂生物信息的巨大储存能力加以利用。尽管这一技术研究取得了成功,但在大多数试验中,DNA分子是悬浮在充满液体的试管中的。史密斯小组把DNA分子的活动限制在固体表面上。这使技术得到简化,尽管仍无法用它造出可像常规计算机那样解决复杂问题的大型DNA计算机。经数年研究,史密斯小组造出了几台DNA计算机,每台都由100万亿个人工合成的NDA链状结构组成,研究人员对DNA链状结构进行编码,使之针对某个待解决问题能包含所有可能的答案。这些结构能反复解决这个问题,但需要人工帮助把这些DNA链栓到一块盖着薄薄的金片的玻璃上,然后反复地浸入不同的酶溶液中,使酶与DNA发生相互作用,剔除掉不当的答案。每台“计算机”在数天时间里可以进行数项不同的计算。美国自1994年起就有十来个研究小组从事分子计算研究。杜克大学的教授说:“利用生物技术进行计算的方法有多种,目前还不大清楚哪一种方法将脱颖而出。”普林斯顿大学教授劳拉的小组致力于开发利用RNA分子的计算潜力,她的小组最近改造了RNA链,使其能处理类似于下国际象棋时遇到的复杂问题。她说,史密斯小组的化学计算机可以解决16种可能答案的问题,而普林斯顿的RNA计算机可以搜索到512种可能的答案。

A.DNA计算技术是一种利用生物技术进行计算的技术

B.DNA计算技术的研究与开发涉及生物学与化学领域

C.DNA计算技术是根据DNA对生物信息的加工储存原理设计的

D.DNA计算技术的研究正逐步深入,但目前尚未取得成功

答案

参考答案:D

阅读理解

阅读下列材料, 然后根据材料内容完成所提问题。

     John Brown, an office worker, lives in Washington, and he inherited (继承) $1 000 000 when he was

23. He didn't feel happy at all. His college friends were looking for their first jobs, but he didn't have to.

John decided to keep living a simple life like everyone else. He didn't tell any of his friends and gave $100 000

of his money to a charity (慈善团体) that helped poor children to live better lives. Today he is 36. He still

wears cheap shoes and clothes and owns a small car only, but he is much happier.

     Up to now John has helped 15 children from poor countries all over the world, $200 a month for each.

The child does not receive the money in cash (现金). The money pays for the child's school expenses, food,

medical care and clothing. John receives a report each year on the child's progress. They can write to each

other, but usually the children do not speak English.

     When John first heard about these children, he wanted to help them."It was not anything special," he said.

"Until I had the chance to go to these countries and meet the children I was helping, I did not know anything

about the type of life they had."

     Once John went to meet a little girl in Africa. He said that the meeting was very exciting."When I met her,

I felt very happy," he said,"I saw that the money was used for a very good plan. It brought me closer to the

child in a way that giving money alone cannot.""I want to do everything I can. I will go on helping those

children in need," he added.

1. What kind of life is John living? 

    __________________________________________________

2. Did John want to look for a job or stay at home after he got the money?

    __________________________________________________

3. Does John only help the poor children in Africa? 

    __________________________________________________

4. The child receives the money in cash, doesn't he? 

    __________________________________________________

5. Why did John say that the meeting with the little girl was very exciting? 

    __________________________________________________

单项选择题