阅读下面的短文,从每题所给的 A、B、C 三个选项中,选出最佳选项回答问题。
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(女族长). A herd may have as few as 8 or as many as 100 elephants. The other elephants follow the matriarch because she knows how to keep them safe from the 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 10 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 head
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

1.B 2.C 3.A 4.A 5.B

1. 细节理解题：根据第一段内容，象群的首领是年老的母象也就是女族长，并非公象，排除A选项；象群数量最少8头最多100头，且只有一位首领，并非多名首领和成百头大象，排除C选项；第一段最后一句提到女族长知道如何保护象群远离危险，和B选项描述一致，故选B。
2. 细节理解题：根据第二段内容，大象的长记忆可以帮助女族长回忆起过去找到水源的位置，还能回忆起小象渡过湍急河流的最安全地点，对应C选项的“找水和过河”，A、B选项内容在文中没有提及，故选C。
3. 词义猜测题：划线词后紧跟说明“Some rumbling sounds are so low and deep that people are unable to hear them”，即这类声音很低沉、深邃，人类无法听见，可推测rumbling的含义是“低沉的”，故选A。
4. 细节理解题：根据最后一段内容，当狮子试图攻击生病的大象或幼象时，成年大象会围在幼象周围，目的是保护幼象不被天敌伤害，保障幼象的安全，对应A选项，故选A。
5. 主旨大意题：全文分别介绍了大象的群居模式、学习特点、交流方式、防御天敌的行为，整体围绕大象的生活习性展开，A选项“大象为什么群居”、C选项“大象如何躲避攻击”都只是文章的部分内容，不能概括全文，故选B。