Question

In Jurassic Park, DNA was used to clone dinosaurs, which was kept for tens of millions of years. The scientists find trouble, however, when they realize that the cloned creatures are smarter and more dangerous than expected. That’s nothing more than a fiction.

   But could we really clone endangered animals?
   To date, the most successful attempt to do so was the cloning of a gaur, a rare ox-like animal from southeast Asia. Scientists used a cow to bring the cloned baby gaur, named Noah. Two days after birth, however, Noah died from a common bacterial infection. Other endangered species that may be cloned include the African bongo antelope (邦戈羚羊), the Sumatran tiger, the cheetah (猎豹), and the giant panda.

    Next, could we really clone extinct animals?

    In theory? Yes. To do this, you need a well-kept source of DNA from the extinct animals such as wool mammoth (毛象), Tasmanian tiger, or even dinosaur, and a closely related species, still living, which could serve as a surrogate mother.

     In reality? Probably not. On the one hand, it’s not likely that extinct animals’ DNA could survive undamaged for such a long time. Cloning extinct animals as wool mammoth, Tasmanian tiger, or dinosaur is much more difficult due to the lack of properly well-preserved DNA. On the other hand, for example, a gaur can have a cow as a surrogate mother, definitely not a monkey. But what about an extinct animals as unique as the panda? What species could possibly serve as a surrogate mother?
     Cloning presents many exciting possibilities. However, even if extinct animals are brought back, they could not survive in today’s world. Not only do most extinct animals have no habitat to live in, but the other plants and animals they depended on for food may also be gone as well.

60. It can be learned from the text that ________.

A. scientists have cloned the African bongo antelope

B. both the cheetah and the giant panda live in Asia

C. the gaur lives in Asia and is endangered          D. the gaur is an extinct species

61. The underlined words "a surrogate mother" probably refer to a female who ______.

  A. contributes its eggs to another female   B. gives birth to a baby for another female

  C. gives birth to a baby of its own        D. cannot give birth to a baby

62. The difficulty in cloning an extinct species is the lack of ______.

  A. both the well-preserved DNA and plants to live on

  B. both the habitat to live in and the well-preserved DNA

  C. both habitat to live in and plants to live on

  D. both the well-preserved DNA and a surrogate mother

63. In the author’s opinion, it is possible that ______.

  A. some extinct species may be cloned, but not survive

  B. extinct species may be cloned and easily survive

  C. a gaur can have a monkey as a surrogate mother

  D. all the extinct species may be cloned

Answer 1

60、C．从文章的第三段可知，像 African bongo antelope这样的濒危物种只是可能被克隆，但还未被克隆，所以A项错；而guar这种生活在亚洲的动物只是濒危，还未灭绝，所以D项错；另外 the cheetah and the giant panda的栖息地也未在文中说明，所以B项错，本题选C。

61、B．从第三段中的"Scientists used a cow to bring the cloned baby gaur, named Noah"和第六段中的"for example, a gaur can have a cow as a surrogate mother"可知克隆的印度野牛（gaur）是科学家利用一头普通的奶牛进行代孕而出生的，奶牛和印度野牛只是近亲，并不是同一物种。"surrogate mother"意为代孕雌性，答案选B。

62、D．由第六段可知，克隆濒危物种既需要保存完好的DNA，也需要有可以代孕的相近物种，而栖息地等问题是克隆物种诞生后面临的生存问题，并非克隆过程中需要面对的困难，所以答案选D。

63、A．从最后一段可知，一些灭绝的物种可能被克隆出来，但在克隆过程中存在困难，而且还会在新的环境中面临生存难题，很难存活。本题选A。