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本帖最后由 cyanidin 于 2010-11-22 18:42 编辑
考点分析,不知道这个活动里面要求了没有。。。
TPO 13 – Lecture 2
Narrator:
Listen to a part of a lecture in an ecology class.
Professor:
So, continuing our discussion of ecological systems【当时听得时候教授是加重读了这个词,前面我觉得语速一下子适应不了,可能是太久没有听过的原因,所以只听到了这一个词】--- whole systems. The main thing to keep in mind here is the interrelationships【这个词也是听到了的,但是脑子中反应不过来是什么意思,太快了——】.
The species in the system err…. and even the landscape itself, they are interdependent. Let’s take what you’ve read for this weekend and see if we can apply this interdependence idea. Mike?
Student:
Well, um…, how about beavers--- ecosystems with beavers in waterways.
Professor:
Good, good, go on.
Student:
Like, well, you can see how it's so important, cause if you go back before European settled in north America, like before the 1600s, back when native Americans were the only people living here, well, back then there were a lot of beavers, but later on, after Europeans…
【【教授打断学生的地方当时一听到我就觉得会有考题点,我还以为会是listen again的题目,这种题我觉得还比较简单】】
Professor:
OK, wait, I see where you are heading with this, but before we go into how European settlement affected the ecosystem, tell me this--- what kind of environment do beavers live in? 【我觉得这句话很重要,但是当时听的时候脑子里面好像没有存储下来这句话的信息。。。听到了立刻就忘了——。这句话应该属于构架的一句话,通过environment,知道下面讲的必然是生存环境】
Think about what it was like before the Europeans settlers came, we’ll come back to where you were headed.
Student:
OK, well, beavers live near streams and rivers and they block up the streams and rivers with like logs and sticks and mud. You know, they build dams【这句话对我来说真的很重要,应该说没听懂的一部分原因在这里,因为dam我听成了damp。。。之后就悲剧了,其实也怪我,beaver没反应过来!!】】
that really slow down the flow of the stream. So then the water backs up, and creates like a pond that floods the nearby land.
Professor:
And that creates wetlands. OK, tell me more.
Student:
Well with wetlands, it's like there is more standing water, more Stillwater around【【当时听得时候纠结在什么叫做standing water 错过了后面的stillwater。。。】】, and that water is a lot cleaner than swiftly flowing water【【听的时候主观的想法太多,一听到更干净立刻觉得是流动的,没有意识到than because】】, because the dirt and settlement and stuff has the chance to sink to the bottom.
Professor:
More important for our discussion, wetland areas support a lot more variety of life than swiftly flowing water. For example, there are more varieties of fish or insects, lots of frog spices, and then species that rely on those species start to live near the wetlands too.
Student:
Yes, like birds and mammals that eat the fish and insects, and you can get trees and plants that begin to grow near the standing water, that can't grow near the running water. Oh, and there's something about wetland, and ground water too.【这也是一个结构点,就是说下面要讲ground water了,可以从女生的口气判断】】
Professor:
OK, good. Wetlands have a big affect on ground water【groundwater 被wetlands作用,wetlands被beaver作用,结构逐渐出来了】, the amount of water below the surface of the land. Think of wetlands as, Umm, like a giant sponge, the earth soaks up a lot of this water that's continually flooding the surface, which increases the amount of water below. So where is there a wetland, you get a lot of ground water, and ground water happens to be a big source of our own drinking water today.【【我们的一大资源就是groundwater,那么,人又被ground作用,而人又捕杀了beaver】
All right… So, back to the beavers, what if the beavers weren't there?
Student:
You just have a regular running stream, because there is no dam, so the ecosystem would be completely different, there would be fewer wetlands.
Professor:
Exactly, so, now let's go back to where you were headed before, Mike. You mentioned the change that occurred after Europeans came to North America.
Student:
Yeah, well, there used to be beavers all over the place, something like 200 million beavers, just in the continental United States. But when Europeans came, they started hunting the beavers for their fur, because beaver fur is really warm, and it was really popular for making hats in Europe. So the beavers were hunted a lot, overhunted, they are almost extinct by the 1800s, so… that meant fewer wetlands, less standing water.【【考点,很重要,当时没听到就做错题了】】
Professor:
And what does that mean for the ecosystem? Kate?
Student:
Well if there is less standing water than the ecosystem can support its many species, because a lot of insects and fish and frogs can't live in running water, and then the birds and animals that eat them, lose their foods supply.
Professor:
Precisely, so the beaver in this ecosystem is what we call a keystone species. The term keystone kind of explains itself. In architecture, a keystone in an archway or doorway is the stone that holds the whole thing together, and keeps it from collapsing. Well, that's what a keystone species does in an ecosystem. It's the critical species that keeps the system going. Now, beaver populations are on the rise again, but there is something to think about.
Consider humans as part of these ecosystems, you've probably heard about water shortages or restrictions on how much water you can use, especially in the summer time, in recent years. And remember what I said about groundwater; imagine if we still have all those beavers around, all those wetlands. What would our water supply be like then?
总结一下,可能太久没听了,第一遍觉得语速超快,一下子不能习惯。觉得听的时候还是抓不到重点,有所退步。 |
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