[单项选择]Human cloning is unlikely to happen because ______.
A. people feel cloned children may not live longer than those naturally born
B. cloning technology is not so advanced that people feel doubts about it
C. it is so expensive that ordinary people have no access to it
D. it is not only costly and inefficient, but unacceptable as well

[单项选择]

Human cloning(克隆) technology could be used to reverse heart attacks. Scientists believe that they may be able to treat heart attack victims by cloning their healthy heart cells and injecting them into the areas of the heart that have been damaged, and other problems may be solved if human cloning and its technology are not forbidden.
·With cloning, infertile couples could have children. Current treatments for infertility, in terms of per- (百分比), are not very successful. Couples go through physically and emotionally painful procedures for a small chance of having children. Many couples run out of time and money without successfully having children. Human cloning could make it possible for many more infertile couples to have children than ever be- fore.
·We should be able to clone the bone marrow(骨髓) for children and adults suffering from leukemia (白血病), This is expected to be one of the first benefits to come from cloning technology.
·W
A. the treatment of heart attacks
B. the bearing of babies
C. the cure of blood diseases
D. the detection of gene-related diseases

[单项选择]The assumption _____ human cloning rests is that all genetic cells contain exact copies of the original set o9f genetic instructions.
A. on which
B. on that
C. at which
D. which

[单项选择]There is unlikely any life on Venus because ______.
A. the surface is too hot
B. the weather is too cold
C. it is severely short of water
D. it has a very thin atmosphere

[单项选择]

"I’ve never met a human worth cloning," says cloning expert Mark Westhusin from his lab at Texas A&M University. "It’s a stupid endeavor." That’s an interesting choice of adjective, coming from a man who has spent millions of dollars trying to clone a 13-year-old dog named Missy. So far, he and his team have not succeeded, though they have cloned two cows and expect to clone a cat soon. They just might succeed in cloning Missy this spring -- or perhaps not for another 5 years. It seems the reproductive system of man’s best friend is one of the mysteries of modern science.
Westhusin’s experience with cloning animals leaves him upset by all this talk of human cloning. In three years of work on the Missy project, using hundreds upon hundreds of dog’s eggs, the A&M team has produced only a dozen or so embryos (胚胎) carrying Missy’s DNA. None have survived the transfer to a surrogate (代孕的) mother. The wastage
A. animal cloning is not worth the effort at all
B. animal cloning is absolutely impractical
C. human cloning should be done selectively
D. human cloning is a foolish undertaking

[单项选择]What will probably happen because of this trade war
A. Demand for wooden houses will fall.
B. Customers will have to pay high prices.
C. Canada will place higher tax on lumber industry.
D. The U.S. will negotiate the matter in good faith.

[单项选择]Human beings differ from animals because they can
A. adapt to their environment.
B. control their environment.
C. adapt the environment to their need.
D. observe and understand their environment.

[单项选择]Human beings are afraid of rats mainly because ______.

[单项选择]The arguments that cloning will have harmful effects ______.
A. are very convincing
B. have forced people to stop cloning
C. have forced people to question the concept of cloning
D. have compelled people to debate the implications of cloning

[单项选择]Which of the following statements about cloning technology is true
A. Because of the criticism, it has been stopped
B. Because of the opposition, it will be illegal for five years
C. Although it is criticized, it has made great progress
D. Although it is criticized, it is a perfect technology