[originaltext] Scientists say sharks have lived in the world’s oceans for mi

游客2024-05-08  14

问题  
Scientists say sharks have lived in the world’s oceans for millions of years. Scientists say there are more than 350 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 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. 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.

选项 A、Call on people to protect sharks.
B、Point out the living environment of sharks.
C、Explain why the sharks are dangerous.
D、An introduction to sharks.

答案 D

解析 推理判断题。原文分别阐述了鲨鱼的种类,鲨鱼的嗅觉,鲨鱼的生产方式,鲨鱼在科学研究上的重要性。A选项是号召人们保护鲨鱼;B选项是说鲨鱼的生存环境;C选项是说鲨鱼为什么是危险的,都不是对这四段的概括。只有选项D对鲨鱼的介绍,可以看作是对这四段的概括。答案是D。
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