【正确答案】 D

【答案解析】[听力原文] 17-20
Scientists say sharks have lived in the world's oceans for millions of years. Scientists say there are more than three-hundred-fifty different kinds of sharks.
Sharks do not have bones, and a shark has an extremely good sense of smell. It can find small amounts of substances in the water, such as blood, body liquids and chemicals produced by animals. Sharks also sense electrical and magnetic power linked to nerves and muscles of living animals. These powerful senses help them find their food. Some sharks will eat just about anything. Many unusual things have been found in the stomachs of some tiger sharks. They include shoes, dogs, a sow's foot and metal protective clothing.
About forty percent of the different kinds of sharks lay eggs. The others give birth to live young. Some sharks carry their young inside their bodies like humans do.
Scientists are beginning to understand the importance of sharks to humans. Medical researchers want to learn more about the shark's body defense system against disease. They know that sharks recover quickly from injuries. Sharks appear never to suffer infections, cancer or heart diseases.

[试题分析] 本题考查的是对整篇文章的理解。
[详细解答] 听遍全文，我们可以得出结论：本文是一篇介绍鲨鱼的科普文章，因此答案是D。

【正确答案】 B

【答案解析】[试题分析] 本题需要的是综合判断能力。
[详细解答] 原文中有这样几句话：“a shark has an extremely good sense of smell”，“Sharks also sense electrical and magnetic power linked to nerves and muscles of living animals. These powerful senses help them find their food.”因此就可以得出答案是B。

【正确答案】 C

【答案解析】[试题分析] 本题测试的是对句意的理解。
[详细解答] “The others give birth to live young. Some sharks carry their young inside their bodies like humans do.”从此句，我们可以看出鲨鱼和人类的相似之处正是生产方式相同。

【正确答案】 B

【答案解析】[试题分析] 本题测试的是文章的细节部分。
[详细解答] “Medical researchers want to learn more about the shark's body defense system against disease”，从这句可以看出，对人类来说，鲨鱼的研究价值就是它那近乎完美的对疾病的抵抗系统。