Can dolphins talk? Maybe they can't talk with words, but they talk with sounds．They show their feelings with sounds．
Dolphins travel in a group．We call this group a "school"．They don't study, but they travel together．Dolphins talk to the other dolphins in the school, They give information about when they are happy or sad or atraid．They say "welcome" when a dolphin comes back to the school．They talk when they play．
They make a few sounds above water．They also make many more sounds under water, but people can't hear these sounds．These sounds are on a higli frequency(频率)．It means they are out of the hearing range(范围)of people．Scientists make tapes of the sounds with special equipment and study them．
Sometimes, people catch a dolphin for a large aquarium．People can watch the dolphins in a show．Dolphins don't like to be away from their school in an aquarium．They are sad and lonely．
There are many stories about dolphins．They help people．Sometimes a dolphin will save somebody's life．Dolphin meat is good, but people don't like to kill them．They say that dolphins bring good luck．Many people believe this．
(1)
Dolphins show their feelings with ________．
[ ]
A．
their eyes
B．
words
C．
water
D．
sounds
(2)
People can't hear dolphin's sounds under water because ________．
[ ]
A．
the sounds are on quite a low frequency
B．
them is no sound under water at all
C．
the sounds are out of people's nearing range
D．
dolphins don't make sounds under water
(3)
What do dolphins do in the "school"?
[ ]
A．
They study and travel together．
B．
They talk to other animals in the sea．
C．
They never talk when they play．
D．
They give information and show feelings．
(4)
What does the underlined word "aquarium" mean in Chinese in this passage?