Sun bears（马来熊）are the smallest of the world's eight bears species（物种）． They have a black coat and a white or golden colour on their bodies． Their homes are in the tropical（热带雨林）of Southeast Asia． They live in trees and eat both plants and animals． They can grow to be 1.4 metres in height and 65 kilograms in weight． They usually live alone and are happy to spend most of their time by themselves．

    Scientists studied sun bears in the Bornean Sun Bear Conservation Center． They found that although sun bears live alone， they have developed a surprising social skill． They can copy （模仿） other sun bear's facial expression （面部表情） as a form of communication． They can even copy exact muscular （肌肉的） movements that other sun bears make﹣ such as making a face．

    The ability to copy facial expressions is found in humans， gorilla's （大猩猩）， some monkeys and some other animals． But until now， only humans and gorillas have the ability to exactly copy facial expressions． However， scientists found that sun bears can copy facial expression as well as humans and gorillas． This surprised them because sun bears are alone and they have no close relationship with human beings．

    Although they live alone in the wild， the sun bears in the study often played gently with each other． Sometimes they played with faster actions as hitting and biting． Scientists are still not sure what messages the sun bears were sending to one another．

（1）According to the passage， where do sun bears usually live？　　

A． In caves．

B． In trees．

C． By the river．

D． On the ice．

（2）From the passage， we can learn something about sun bears EXCEPT that　　．

A． they like to live alone in the wild and only eat animals

B． they can copy other sun bears' facial expressions for communications

C． they can copy exact muscular movements of other sun bears

D． they have no close relationship with human beings

（3）Which of the following might be the best title for the passage？　　

A． A warm home on the earth

B． A brave animal in the forest

C． A new friend of human beings

D． A surprising skill of sun bears