【正确答案】 D

【答案解析】
[听力原文]13-16
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.
(14[B]) 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 large sharks. They include shoes, dogs, a cow's foot and metal protective clothing.
About forty percent of the different kinds of sharks lay eggs. The others give birth to live young. (15[C]) Some sharks carry their young inside their bodies like humans do.
Scientists are beginning to understand the importance of sharks to humans. (16[B]) 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.

主旨题。本文围绕着鲨鱼(sharks)的生活习性展开，依次说明了它的身体特征，捕食方法，繁殖方式和对疾病的抵抗性等。因此[D]为正确．[A]，[C]与本文无关，[B]太片面。

【正确答案】 B

【答案解析】细节题。文章中说：鲨鱼有极其敏锐的嗅觉(good sense of smell)，能找到水里很小的物质，如动物的血、尸体等。鲨鱼同样也能用连接神经和肌肉的电磁感应来感知生物(sense electrical and magnetic power)。这些强有力的感觉帮助鲨鱼找到食物。由此可以看出鲨鱼靠敏锐的嗅觉和电磁感觉来捕食猎物。

【正确答案】 C

【答案解析】细节题。文章中说：部分鲨鱼的生育方式与人类一样(carry their young inside their bodies like humans do)，可见选项[C]与这句话意思一致。

【正确答案】 B

【答案解析】推理题。文章中说：医学研究者们希望更多地得知鲨鱼机体抗病系统的原理。可以看出人类渴望通过研究鲨鱼的抗病机理以期对人类有帮助，因此选项[B]是正确的。