[单项选择]

Interesting as dolphins (海豚) are to scientists, it is their intelligence and sociability that have caught the popular imagination. Like whales, dolphins have a strong sense of family. A dolphin family is like a human family, but much larger.
Dolphins seem to be among the most sociable of all living creatures. They enjoy playing with each other and also with the humans, with whom they come in touch. It is this characteristic that makes them so easy to train as star performers. Besides, they seem able to remember humans that they have met even when there is a long period of time between meeting.
A sense of family and a spirit of cooperation appear to be very strong among all these marine animals. There are many recorded cases of dolphins supporting a sick animal on the surface of the water so that it will be able to breathe.
Language has always been considered unique to human beings. It now seems that the cetaceans (鲸目动物) may be able to communicate with each
A. a language unknown
B. sounds that are a real language
C. sounds that approach a real language
D. their brains

[单项选择]

Interesting as dolphins (海豚) are to scientists, it is their intelligence and sociability that have caught the popular imagination. Like whales, dolphins have a strong sense of family. A dolphin family is like a human family, but much larger.
Dolphins seem to be among the most sociable of all living creatures. They enjoy playing with each other and also with the humans, with whom they come in touch. It is this characteristic that makes them so easy to train as star performers. Besides, they seem able to remember humans that they have met even when there is a long period of time between meeting.
A sense of family and a spirit of cooperation appear to be very strong among all these marine animals. There are many recorded cases of dolphins supporting a sick animal on the surface of the water so that it will be able to breathe.
Language has always been considered unique to human beings. It now seems that the cetaceans (鲸目动物) may be able to communicate with each
A. They are very interesting.
B. They are very intelligent.
C. They are sociable.
D. All of the above.

[填空题]Dolphins(海豚) are intelligent and quick to learn; they also have a curious (express)（）.

[单项选择]Dolphins (海豚) live their whole lives in water. But they are mamma& (哺乳动物J) that live in water. That’ s why a dolphin comes to the top of the water so often. A dolphin’ s nose isn’ t easy to see. It’ s just a tiny hole on top of the dolphin’ s head. This hole is called a blowhole. A dolphin comes up every half minute or so to breathe. It opens its blowhole and takes in air. Then it closes its blowhole tight and dives into the water again. But a dolphin can stay under the water for six or seven minutes if it has to. It holds its breath.
A dolphin hears with two ears. It hears all sorts of small noises under water. It hears small stones rolling. It can hear sounds fish and other dolphins make. A dolphin’s ears may be extra small, but its mouth is extra big. It has to be big. It holds almost one hundred teeth. These teeth are all the same shape and size. They are used for catching food, but not for chewing (咀嚼) it. A dolphin opens its big mouth. It seizes (抓住) a fish firmly between it
A. are used to chew food
B. are all the same as the ape’s
C. can swallow a whole fish
D. are used to catch food