题目内容：

 Directions: Read the following passage. Complete the diagram by using the information from the passage.

Write NO MORE THAN THREE WORDS for each answer.

Dolphins are not fish; they’re mammals. They are warm-blooded like man and give birth to one baby called a calf at a time. At birth a calf is about 90—130cm long and grows to about 4m. They live up to 40 years. They are highly sociable animals.

Their teeth are interlocking rows of hooks, suitable for holding slippery fish. They eat fish whole starting with head first. When they go wild they keep their mouth open and sometimes keep it nodding to express their aggression. Greater aggression is shown by violent jaw clapping. Dolphins breathe through their blowhole(呼吸孔) located at the top of their head. The dolphin’s eyes produce a special slippery secretion(分泌物) which protects the eyes from foreign objects and water friction.

Dolphins use their powerful tail to move through the water. They also use their tail while hunting. They slap their tail rapidly when they get annoyed or when they want to indicate the sign of danger to alert other dolphins.

The dolphin’s skin is completely smooth allowing the dolphin to move easily through the water, and also reduce heat loss. Their skin may bear rake marks from other dolphin’s teeth during play or mating, and can easily become badly sunburned if they strand(搁浅).

Their bodies are very streamlined so they may swim at high speed through the water, and an example of this is their ears. Dolphin’s ears are barely noticeable marked only by a small hole just behind the eyes.

While sleeping, it shuts down only half of its brain, as its breathing is under voluntary control. Dolphins take short catnaps, floating just below the surface, and then slowly rising to breathe. Often dolphins are very active during night time, for some this is their main feeding time. Dolphins are able to dive to great depths, and also leap to great heights. They may leap to avoid predators or to show how powerful they are to females at mating time.

Title: 71.___________ Ⅰ. Characteristics ● mammals : warm-blooded animals and one baby at a birth ● length : 90cm-4m ● lifespan : 40 years ● highly sociable animals Ⅱ. 72.___________ ● teeth→ holding slippery fish and eating fish whole 73.__________ ● opening and nodding mouth→ expressing their aggression ● 74._________ jaw→ expressing greater aggression ● blowhole at the top of their head→ 75.____________ ● eyes with a special slippery secretion→ protecting the eyes from foreign objects and water friction ● 76._____________ ears→ swimming at high speed through the water Ⅲ. Tail ● powerful to move through the water ● 77.___________ and expressing annoyance and danger Ⅳ. 78.___________ ● completely smooth to move easily through the water and reduce heat loss ● full of rake marks to become badly sunburned easily Ⅴ. Body ● 79._____________ to swim at high speed through the water Ⅵ. Habitual nature ● short catnaps with only half of its brain ● 80.___________ breathing ● activities during night time for feeding