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 (獵豹), 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．從文章的第三段可知，像 African bongo antelope這樣的瀕危物種只是可能被克隆，但還未被克隆，所以A項錯；而guar這種生活在亞洲的動物只是瀕危，還未滅絕，所以D項錯；另外 the cheetah and the giant panda的棲息地也未在文中說明，所以B項錯，本題選C。

61、B．從第三段中的"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）是科學(xué)家利用一頭普通的奶牛進(jìn)行代孕而出生的，奶牛和印度野牛只是近親，并不是同一物種。"surrogate mother"意為代孕雌性，答案選B。

62、D．由第六段可知，克隆瀕危物種既需要保存完好的DNA，也需要有可以代孕的相近物種，而棲息地等問題是克隆物種誕生后面臨的生存問題，并非克隆過程中需要面對的困難，所以答案選D。

63、A．從最后一段可知，一些滅絕的物種可能被克隆出來，但在克隆過程中存在困難，而且還會在新的環(huán)境中面臨生存難題，很難存活。本題選A。