最新step_by_step3000第三册unit6答案及原文

Unit 6 Science and Technology

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Part I Warming up

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A1.3

Tapescript.

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1. Thai silk is known for its beauty and elegance. But a research team has found a new

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use for it. A bulletproof vest made of silk was put to the test at a shooting range in 6

Thailand. After several rounds of gunfire, the vest was examined. The bullets were stuck 7

in the first layer of fifteen pieces of silk. A member of the research team says while 8

silk threads may be soft, they can be used to produce a stronger yarn than copper threads, 9

the material used in regular bulletproof vests.

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2. American and Japanese researchers say they are a step closer to predicting severe

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weather in and around the Indian Ocean. Researchers have analyzed weather data from the

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region over the past 40 years and they've discovered a strong connection between extreme

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weather and conditions in the ocean. A BBC science correspondent says the findings could

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make it easier to predict droughts or, indeed, periods of heavy rainfall.

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3. The world chess champion Garry Kasparov began a match against the rest of the world

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on the Internet. Kasparov made his first move with a meter-high pawn before an audience

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of chess fans at a park in New York. The move was immediately posted on a special website

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set up by the Microsoft corporation. Visitors to the site have 24 hours to vote on their

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counter move helped by a team of young chess experts who will suggest strategies.

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4. Few scientific advances of this or any millennium can rival in significance the

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discovery of the structure of DNA, the basic molecule of life. Knowledge of the structure

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of DNA helps explains many things, including genetic mutation and , through it, evolution.

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Understanding its code has helped to unlock the mechanics of inherited disease, as well

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as beneficial biological traits such as intelligence and body strength. The discovery of

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the DNA molecule also paved the way for many of today’s cutting-edge sciences, including

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genetic engineering, a controversial branch of knowledge that raises new ethical and moral

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questions that are certain to be with us far into the next millennium.

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5. Some say it's hard to find good help these days, but a Japanese electronics firm thinks

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it's found the answer. It's a robot that talks and understands orders. The robot from NEC

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can record and send video mail through the Internet and switch on TVs and VCRs. And if

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it's becoming a bit warm for you, one simple command and the robot will switch on the air

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conditioner.

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B.35

Tapescript:

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1 .... Yes, you see, it's the force of attraction between any two objects. The strength

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of the force depends on the mass of the objects and the distance between them. Er... the

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most obvious effect is the way objects on the surface of the earth are attracted towards

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the center of the earth...

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2 .... as it comes down it goes relatively slowly 100 to 1,000 miles per hour and you

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can't see it, but the return stroke goes up from the earth to the cloud and it goes at

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over 87,000 miles per hour and that's the one you can see, you see, the one that goes back

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up. It's really just a very large, powerful spark. The distance in miles you are away from

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it is the time in seconds between it and the sound you hear...

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3 .... Well, they were first discovered in 1895 and they can penetrate matter that is

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opaque to light. Some matter is more transparent to them than others, which means you can

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