Many people say dolphins are very intelligent．They seem to be able think，understand，and learn things quickly．But they are smart like humans or more like cats or dogs？Dolphins use their brains differently from people．But scientists say dolphin intelligence and human intelligence are alike in some ways．How？

FACT 1：Talk to Me

Like humans，every dolphin has its own"name"．The name is a special whistle（口哨声）．Each dolphin chooses a specific whistle for itself，usually by its first birthday．Actually，scientists think dolphins，like people，"talk"to each other about a lot of things，such as their age，their feelings，or finding food．And，like humans dolphins use a system of sounds and body language to communicate．But understanding their conversations is not easy for humans．No one"speaks dolphin"yet，but some scientists are trying to learn．

FACT 2：Let's Play

Dolphins are also social animals．They live in groups called pods，and they often join others from different pods to play games and have fun---just like people．In fact，playing together is something only intelligent animals do．

FACT 3：Fishermen's Helpers

Dolphins and humans are similar in another way：both make plans to get something they want．In the sea of southern Brazil，for example，dolphins use a interesting strategy to get food．When fish are near a boat，dolphins signal to the fishermen to put their nets in the water．Using this method，the men can catch a lot of fish．What is the advantage for the dolphins？Why do they assist the men？The dolphins get to eat some of the fish．

56．What is the text mainly about？___

A．The comparison between dolphins and humans．

B．The relationship between dolphins and humans．

C．Different types of dolphins．

D．The habitual behavior of dolphins．

57．What can we learn about dolphins according to the text？___

A．A dolphin gets its food from its mother．

B．Dol