- Lesson1 Finding Fossil Man.
- Lesson2 Spare that spider.
- Lesson3 Matterhorn Man.
- Lesson4 Seeing hands.
- Lesson5 Youth .
- Lesson6 The sporting spirit.
- Lesson7 Bats.
- Lesson8 Trading standards.
- Lesson9 Royal Espionage.
- Lesson10 Silicon valley.
- Lesson11 How to Grow Old .
- Lesson12 Banks and their customers.
- Lesson13 The Search for Oil .
- Lesson14 The Butterfly Effect.
- Lesson15 Secrecy in Industry.
- Leaaon16 The modern city.
- Lesson17 A Man-made Disease.
- Lesson18 Porpoises.
- Lesson19 The Stuff of Dreams.
- Lesson20 Snake poison.
- Lesson21 William S. Hart and the Early Western Film .
- Lesson22 Knowledge and progress.
- Lesson23 Bird Flight.
- Lesson24 Beatuy.
- Lesson25 Non-Auditory Effects of Noise.
- Lesson26 The past life of the earth.
- Lesson27 The vasa.
- Lesson28 Patients and doctors.
- Lesson29 The Hovercraft.
- Lesson30 Exploring the sea-floor.
- Lesson31 The Sculptor Speaks.
- Lesson32 Galileo reborn.
- Lesson33 Education.
- Lesson34 Adolescence.
- Lesson35 Space Odyssey.
- Lesson36 The cost of government.
- Lesson37 The Process of Ageing.
- Lesson38 Water and the traveller.
- Lesson39 What Every Writer Wants.
- Lesson40 Waves.
- Lesson41 Training Elephants.
- Lesson42 Recording an earthquake.
- Lesson43 Are There Strangers in Space.
- Lesson44 Patterns of culture.
- Lesson45 Of Men and Galaxies.
- Lesson46 Hobbies.
- Lesson47 The Great Escape .
- Lesson48 Planning a share portfolio.
New Word and expressions 生词和短语
First listen and then answer the following question.
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 Sea
New words and expressions 生词和短语