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第1段
1 .<-NARRATOR:->Now listen to part of a lecture on the topic you just read about.
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第2段
1 .<-MALE PROFESSOR:->Ethanol actually is a good alternative to gasoline.
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2 .Although you just read three reasons why it’s not a good alternative, not one of these three reasons is convincing:
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第3段
1 .First, the increased use of ethanol fuel will not add to global warming.
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2 .It’s true that when ethanol is burned, it releases carbon dioxide into the atmosphere.
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3 . But as you read, ethanol’s often made from plants such as corn.
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4 .Well, the process of growing the plants counteracts this release of carbon dioxide.
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5 .Let me explain. Every growing plant absorbs carbon dioxide from the air as part of its nutrition.
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6 .So, growing plants for ethanol production actually removes carbon dioxide from the atmosphere.
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第4段
1 .Second, large-scale production of ethanol doesn’t have to reduce the sources of food for animals.
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2 .That’s because we can produce ethanol using cellulose.
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第5段
1 .Cellulose is the main component of plant cell walls, and you’ll find most cellulose in those parts of plants that are not eaten by animals.
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2 .So, since we can produce ethanol from the plant parts that aren’t eaten, the amount of animal feed that’s available will not be reduced.
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第6段
1 .Third, in the future, ethanol will be able to compete with gasoline in terms of price.
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2 .It’s true that government subsidies make ethanol cheaper than it would normally be, but this support won’t always be needed.
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3 .Once enough people start buying ethanol, ethanol producers will increase their production of ethanol. Generally, increased production of a product leads to a drop in its price.
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4 .So the price of ethanol will go down as more of it becomes available.
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5 .Studies show that if ethanol production could be three times greater than it is now, the cost of producing a unit of ethanol would drop by forty percent.
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