【英语时差8,16】森林燃料的可持续发展

Ya?l: Time to go again to the A Moment of Science mailbag. A listener writes: Dear Don and Ya?l, I know that eventually oil will run out and that we'll need to develop alternative sources of energy. And I keep hearing about things like wind and solar power and hydrogen¹ fuel cells. But which of these seems most likely to emerge² as a major source of energy in the future? Don: Good question. Of course, wind and solar power will most likely play roles, as well as nuclear power. But there's another potential source of renewable energy that you don't hear as much about--forests. Y: Wait, you mean like chopping³ down trees and using wood as fuel? D: Sort of. Y: But won't that lead to deforestation? That's what happened a few hundred years ago, before coal, when wood was the main source of energy and we cut down entire forests. D: True, but that's not what I'm talking about. Some energy scientists today see forests as sources of renewable energy. For example, forest biomass, meaning leaves and stems⁴ and small trees and other plants, can be used to make ethanol. Forest biomass can also be used to produce charcoal-like pellets that can be burned for energy. Y: OK, but we're still talking about cutting down trees, right? D: Yes, but not all the trees at once. And forest scientists know that cutting out smaller trees and plants is actually good for forests. When forests become too crowded with trees competing for light and water, biodiversity tends to suffer. So careful thinning out of forests can be healthy. Y: Interesting. So maybe one day we'll be running on forest power. D: Maybe.

1 hydrogen   

n.氢元素，氢气

参考例句：

• Water is made up of atoms of hydrogen and oxygen.水由氢和氧的原子构成。
• A chemist can isolate the oxygen from the hydrogen in water.一个化学家能把水中的氧和氢分解。

2 emerge   

vi.（从水中等）出来，出现，浮现，形成

参考例句：

• The baby's head was starting to emerge from the womb.婴儿的头开始从母亲的子宮中露出来。
• It's still hard to tell who will emerge victorious.鹿死谁手尚难逆料。

3 chopping   

adj.波浪汹涌的，硕大强健的；削球；斩波；断续

参考例句：

• He was preparing fodder, chopping finely and mixing thoroughly. 他在准备饲料，把它切碎，拌好。 来自《简明英汉词典》
• This fellow is always chopping and changing; he's very unreliable. 这个人反复无常，很不可靠。 来自《现代汉英综合大词典》

4 stems   

n.（花草的）茎( stem的名词复数 )；词干；（高脚酒杯的）脚；烟斗柄v.遏制[阻止]（液体的流动等）( stem的第三人称单数 )；封堵；遏止

参考例句：

• The present wave of strikes stems from discontent among the lower-paid. 当前的罢工浪潮起因于低工资雇员们的不满情绪。 来自《简明英汉词典》
• Her interest in flowers stems from her childhood in the country. 她对花卉的兴趣产生于她在乡下度过的童年时代。 来自《简明英汉词典》