Elephants are the largest land animals alive today． African elephants live in family groups called herds（群）． All of the elephants in the herd take care of each other． The leader of the herd is an old mother elephant． She is the matriarch （族长）． A herd may have as few as eight or as many as 100 elephants． The other elephants follow the matriarch because she knows how to keep them safe from coming danger．

    Elephants learn by watching and copying other elephants， and also learn from life． Baby elephants stay with their mothers until they are fully grown at about ten years old． Elephants live to be 50 or 60 years old． Elephants are smart animals with long memories． In the dry season， a matriarch can remember where water was found in the past． The herd will follow her there． She can also remember the safest place for baby elephants to cross a fast﹣moving river．

    Elephants talk to each other with rumbling sounds． Some rumbling sounds are so low and deep that people are unable to hear them． Elephants hear sounds not only with their ears， but also with their feet， and even trunks （long noses of the elephants）． They also greet each other by touching with their trunks and feet． If danger appears， mothers beat their ears to call their babies to them．

    Other animals don't usually attack（攻击） elephants． However， a lion might try to attack a sick elephant or a baby． If this happens， the adult elephants circle around the baby elephants． The adults make louder sounds and hit the ground with their trunks． The matriarch puts herself between the lion and the herd． She beats her ears out to make herself look even larger． Then she lowers her herd and attacks the enemy（敌人） in a big cloud of dust（灰尘）．

（1）According to Paragraph（段落） One， an elephant herd　　．

A． has a father elephant as the leader

B． owns a matriarch who keeps it away from danger

C． always has several leaders and hundreds of elephants

（2）Long memories help elephants to　　．

A． choose their matriarch

B． communicate with each other

C． find water and cross the river

（3）What does the underlined word "rumbling" mean？　　

A．低沉的

B．尖细的

C．高亢的

（4）Why do the adult elephants circle around their babies？　　

A． To keep their babies safe．

B． To welcome their friends．

C． To attack their enemies．

（5）The passage mainly tells us about　　．

A． why the elephants live in herds

B． what the elephants' living habits are

C． how the elephants avoid being attacked