We know people can be nice，but what about animals？

       Scientists say that some animals are capable（有能力的） of being nice．Animals that live in groups﹣like foxes，chimpanzees （大猩猩），and elephants﹣follow rules．They have to followrules to get along and to survive（生存）．However，animals can act nicely，even when they don't have to． Here are some surprising stories about animal behavior．

       Most people usually walk away when someone is unkind to them．Marc Bekoff，a researcher at the University of Colorado，saw a female （母的）red fox do just that． The female fox was unhappy because a male（公的）fox played roughly（粗鲁地）with her．When she walked away，the male fox showed her that he wanted to play nicely．He lowered his head and rolled on his back．The female fox gave him another chance，and this time，he played more gently．

       Geza Teleki is a scientist who studies chimpanzees in Tanzania．One day，Teleki hiked far away from his campsite．He didn't have any food．Teleki wanted some fruit from a tree，but the tree was too tall． A young chimpanzee watched him curiously as he tried to get something to eat．The chimpanzee climbed the tree，picked the fruit，and gave it to him!

       An elephant in Kenya hurt his trunk（象鼻子）．He needed help because he couldn't put food into his mouth．Researcher Kayhan Ostovar watched silently．He saw the hurt elephant show his sore trunk to a healthy elephant．The healthy elephant didn't need any more information．He took a bush and put it carefully into his new friend's mouth．

       Hippos（河马）and crocodiles are usually good friends．They hang out together in rivers．But Karen Paolillo，a wildlife expert in Zimbabwe，saw something surprising．One day，a crocodile tried to eat a monkey that was next to a river．A hippo ran quickly to the crocodile and chased it away．Why did the hippo attack （攻击） the crocodile？ Paolillo says hippos sometimes protect other animals from crocodiles．

（1）The main idea of the passage is　　．

A．animals that live in groupe follow rules

B．some animals can be nice to other animals

C． most animals are nice to people

（2）The underlined phrase"do just that"means　　．

A．be nice

B．play roughly

C．walk away

（3）We can say that Teleki　　．

A．is short

B．hates hiking

C．could not climb the tree

（4）The elephant needed help because　　．

A．the tree was too tall

B． it could not use its trunk

C． it had no food

（5）The underlined word"it"in the last paragraph refers to　　．

A．the crocodile

B．the chimpanzee

C．the monkey