问题 名词解释

交配频率(交配能力)

答案

参考答案:

指在一定的时间内,种公畜与发情母畜交配的次数。

简答题
阅读理解

Reading comprehension.

     Many experts complain that media too often take advantage of the science fiction aspects of nanotech (纳

米技术). Reports of nanotech often refer to K. Eric Drexler's book Engines of Creations, which predicts an

age full of dominant molecular (分子的) manufacturing and a world without material scarcity. Whatever

humans need will one day be built cheaply with microscopic self-replicating machines (微细自我复制机) that

put atoms together to create copies of anything alive in the world-from trees to human bodies.

     In fact, the scientific community is deeply divided over whether self-replication machines are possible. If

they are, major dangers could exist. Mr. Drexler himself thought that self-replicating machines could probably

go out of control. He writes in his book that man-made "plants" with "leaves no more efficient than today's solar

cells could win over real plants,crowding the earth with leaves that are not suitable to be eaten. Tough 'bacteria'

could be more competitive than the real bacteria: They could spread everywhere, replicate swiftly, and reduce

the earth to dust in a matter of days."

     Critics of nanotech have made use of such images, calling for a delay on commercial nanotech until

regulations are established. They also point to the possible military uses of nanotech. Bill Joy, the co-founder of

Sun Microsystems, wrote in a Wired magazine essay in 2000 that if nanotech falls into the wrong hands, it could

bring dangers to society.

     Opponents say Mr. Joy is overreacting. "In a way, calling for bans on research into molecular manufacturing

is like calling for a delay on faster-than-light travel because no one is doing it," says Glenn Reynolds, a University

of Tennessee law professor.

     Professor Reynolds says it is a good idea to regulate nanotech, but in ways the government would regulate

any products that could be dangerous. Export controls and certification systems for nanotech companies are

examples. US lawmakers have put forth four bills on nanotech research and development.

1. K. Eric Drexler in his book predicts a future world with sufficient material, because _____.

A. man-made plants could replace real plants and grow more quickly

B. plants produced by nanotech would be as efficient as today's solar cells

C. man-made bacteria would be widespread and capable of self-replicating

D. humans could create copies of anything alive with high technology

2. To call for a delay on commercial nanotech, critics of nanotech make use of _____.

A. current social problems

B. science fiction descriptions

C. disagreements in the scientific community

D. the fact that no one is doing molecular manufacturing

3. Opponents of Bill Joy would NOT agree to _____.

A. control nanotech export

B. ban nanotech research to avoid any possible dangers

C. put forth bills on nanotech research and development

D. establish a certification system for annotech companies

4. Which of the following statements best summarizes the main idea of the passage?

A. Nanotech should not be put into wrong use in the military field.

B. The government should regulate products that could be dangerous.

C. Nanotech regulations should be established in spite of the divided opinions.

D. The media should not take advantage of the science fiction aspects of nanotech.