题目内容：

    Discover Sharks

Sharks have lived in the oceans for over 450 million years, long before dinosaurs appeared. There are now about 360 kinds of sharks, whose size, behavior, and other characteristics differ widely.

Every year, people catch and kill over 100 million sharks. They hunt sharks for sport, food, medicine and their skin. Experts say the international market for some kinds of sharks has increased because many parts of a shark are valuable. Collectors pay thousands of dollars for the jaws of a shark. Shark liver oil is a popular source of Vitamin A. The skin of a shark can be used like leather. In Asia, people enjoy a kind of soup made from shark fins.

It takes most kinds of sharks10 to 15 years to begin reproducing (繁殖)and most sharks reproduce only every two years. And they give birth to fewer than ten young sharks. For this reason, over-fishing of sharks is the special danger to the future of the animal.

Influenced by movies and popular novels, most people see sharks as people-eating monsters. This is far from the truth. Every year, a few types of shark injure about 100 people worldwide and kill about 25. Most attacks are by great white sharks, which often feed on sea mammals, just like sea lions，sea dogs and dolphins. They sometimes mistake human swimmers for their food, especially if they are wearing black wet suits.

If you are a typical ocean-goer, your chances of being killed by a shark are about 1 in 100 million. You are more likely to be killed by a pig than a shark and thousands of times more likely to get killed when you drive a car.

According to the studies, most sharks can live 20 to 30 years. Although sharks cannot live as long as human beings, they have the similar aging process. Sharks help save human lives. They are helping us learn how to fight cancer and other diseases. Their highly effective immune(免疫的) system allows wounds to get better and their blood is being studied in connection with AIDS research.

Sharks are needed in the world’s ocean ecosystems(生态系统). Although they don’t need us, we need them. We are much more dangerous to sharks than they are to us. For every shark that bites a person, we kill one million sharks.

1.The second paragraph is mainly about ______.

A. why people kill sharks

B. who makes sharks in danger

C. what causes people fear sharks

D. how sharks produce their babies

2.The word ‘‘aging process’’ in Paragraph 6 probably means “ ______”.

A. sharks have their own family

B. sharks live from baby to the old

C. sharks have their own language

D. sharks raise their children all the time

3.What can we learn from the passage?

A. People find dinosaurs have lived long before sharks.

B. One hundred people are killed by sharks every year.

C. Sharks are helping people fight diseases like cancer.

D. Sharks give birth young babies every 10 to 15 years.