13．Dolphins are our friends．They can use tools to solve problems although they don't have hands．For example，scientists have ever found that a dolphin can make a shy eel（鰻魚） come out of its hole with a dead fish．
Dolphins use different sounds to exchange information with each other．Scientists in Hawaii have developed a sign language to give instructions to dolphins，and the results are amazing．They find that dolphins not only understand the meaning of individual （個別的） words，but also understand the importance of word order in a sentence．
Most animals enjoy playing-but dolphins seem to like making their games as challenging as possible．On a beautiful day in 1997，scientists at a beach watched a little dog going into the sea and swimming towards the dolphins．To their surprise，the dolphins came up to the dog and then started throwing it into the air．The dog seemed to enjoy the"game"and continued playing with the dolphins for more than an hour．
Dolphins live in a very different world from ours，but they are very good at our"IQ tests"．For example，they will jump out of the water when they hear a whistle （口哨） noise．They do this because they will get a fish as a prize．
There is still much to learn about these cute problem-solvers，but it is certain that watching a dolphin show is fun．
根據(jù)短文內(nèi)容，選擇最佳答案．（5分）
46．What can a dolphin use to make an eel come out of its hole？C
A．Its mouth．
B．Its head．
C．A dead fish．
D．A little dog．
47．How do dolphins exchange information with each other？D
A．By using tails．
B．By using tools．
C．By using words．
D．By using sounds．
48．Where did the dolphins throw the dog when playing？B
A．Onto its back．
B．Into the air．
C．Onto the beach．
D．Into the water．
49．Why do the dolphins jump out of the water when they hear a whistle noise？A
A．Because they want to get a fish as a prize．
B．Because they enjoy playing on the water．
C．Because they want to play with other dolphins．
D．Because the dolphin keepers want them to come out．
50．Which of the following is TRUE according to the passage？B
A．Dolphins understand many languages．
B．Dolphins are a kind of clever animals．
C．Scientists have known dolphins well enough．
D．Dolphins seem to make their games relaxing．
