新概念英语第四册（美音版）Porpoises(新概念英语第四册课后答案)

Lesson 18Porpoises海豚First listen and then answer the following question.听录音，然后回答以下问题。What would you say is the main characteristic of porpoises?There has long been a superstition among mariners that porpoises will save drowning men by pushing them to the surface, or protect them from sharks by surrounding them in defensive formation. Marine Studio biologists have pointed out that, however intelligent they may be, it is probably a mistake to credit dolphins with any motive of lifesaving. On the occasions when they have pushed to shore an unconscious human being they have much more likely done it out of curiosity or for sport, as in riding the bow waves of a ship. In 1928 some porpoises were photographer working like beavers to push ashore a waterlogged mattress. If, as has been reported, they have protected humans from sharks, it may have been because curiosity attracted them and because the scent of a possible meal attracted the sharks. Porpoises and sharks are natural enemies. It is possible that upon such an occasion a battle ensued, with the sharks being driven away or killed.Whether it be bird, fish or beast, the porpoise is intrigued with anything that is alive. They are constantly after the turtles, who peacefully submit to all sorts of indignities. One young calf especially enjoyed raising a turtle to the surface with his snout and then shoving him across the tank like an aquaplane. Almost any day a young porpoise may be seen trying to turn a 300-pound sea turtle over by sticking his snout under the edge of his shell and pushing up for dear life. This is not easy, and may require two porpoises working together. In another game, as the turtle swims across the oceanarium, the first porpoise swoops down from above and butts his shell with his belly. This knocks the turtle down several feet. He no sooner recovers his equilibrium than the next porpoise comes along and hits him another crack. Eventually the turtle has been butted all the way down to the floor of the tank. He is now satisfied merely to try to stand up, but as soon as he does so a porpoise knocks him flat. The turtle at last gives up by pulling his feet under his shell and the game is over.RALPH NADING HILL Window in the SeaNew words and expressions 生词和短语porpoisen. 海豚marinern. 水手sharkn. 鲨鱼formationn. 队形dolphinn. 海豚科动物unconsciousadj. 不省人事beavern. 海狸ashoreadv. 上岸waterloggedadj. 浸满水的scentn. 香味ensuev. 接着发生intriguev. 引起兴趣indignityn. 侮辱snoutn. 口鼻部shovev. 硬推aquaplanen. 驾浪滑水板oceanariumn. 水族馆swoopv. 猛扑bellyn. 腹部equilibriumn. 平衡buttv. 碰撞crackn. 重击