Ⅰ.阅读理解(根据根据课文内容完成下列各题) 1．Which of the following statements is true about sharks? A．Among nearly 400 different types of sharks, only about 30 types attack human beings. B．The most dangerous sharks are the tiger shark and the bull shark. C．The shark's attack is the leading cause of people's death in the sea. D．The chance of being attacked by sharks is rather small compared to other dangers.