小站备考
托福
托福听力
Official6听力真题

OFFICIAL6 Why does the professor say this?

展开
Tip:单击查看句义;划选/双击查生词

[00:00.00]Narrator: Listen to part of a lecture in a biology class.
[00:05.50]FEMALE PROFESSOR: OK, I have an interesting plant species to discuss with you today. [00:09.73]Uh, it's a species of a ve-e-ry rare tree that grows in Australia, Eidothea hardeniana, but it’s better known as the Nightcap Oak.
[00:18.82]Now, it was discovered only very recently, just a few years ago. Uh, it remained hidden for so long because it's so rare, [00:29.55]there're only about, oh, two hundred of ‘em in existence. [00:33.44]They grow in a rain forest, in a mountain rage range in the north part of New South Wales, which is, uh, a state in Australia. [00:42.29]So just two hundred individual trees in all.
[00:46.60]Now, another interesting thing about the Nightcap Oak is that it is… it represents… a—a very old…type, a kind of a tree that grew…a hundred million years ago. [01:00.06]Uh we found fossils that old that bear a remarkable resemblance to the tree. [01:05.12]So, it's a primitive tree, [01:07.66]a... a living fossil, you might say. [01:09.77]It's a relic from earlier times, and it has survived all these years without much change. [01:15.57]And... it—it’s probably a kind of tree from which other trees that grow in Australia today evolved.
[01:22.29]Just—just to give you an idea of what we're talking about, [01:24.66]here’s a picture of the leaves of the tree and its flowers. [01:27.69]II dunno how well you can see the flowers, [01:30.77]they're those little clusters sitting at the base of the leaves.
[01:34.74]OK, what have we tried to find out about the tree since we’ve discovered it? [01:40.05]Hmm well how... why is… is it so rare? [01:44.79]It is one of the first questions. [01:46.21]Uh, how is it, uh how does it reproduce? [01:50.50]It is another question. [01:51.48]Uh, maybe those two questions are actually related? Jim.
[01:56.69]MALE STUDENT: Hmm, I dunno, [01:58.88]but uh I can imagine that…for instance…uh seed dispersal might be a factor [02:04.24]I mean if the uh y'know if the seeds cannot really disperse in a wide area then you know the tree may not uh colonize new areas, [02:12.55]it can't spread from the area where it's growing.
[02:15.11]FEMALE PROFESSOR: Right, that’s that’s actually a very good answer. [02:18.24]Uh, of course, you might think there might not be many areas where the tree could spread into, uh because uh well it's it's very specialized in terms of the habitat. [02:29.43]But that’s not really the case here, [02:31.90]uh the the suitable habitat habitat that is the actual rain forest is much larger than than the few hectares where the Nightcap Oak grows.
[02:40.76]Now, this tree is a flowering tree as I showed you, [02:43.94]uh uh, it—it produces a fruit, much like a plum, [02:48.52]on the inset inside there's a seed with a hard shell. [02:51.55]Uh it it appears that the shell has to crack open or break down somewhat to allow the seed to soak up water. [02:58.34]If the Nightcap Oak remains if their seeds remain locked inside their shell, they will not germinate. [03:05.29]Now actually the seeds, uh they don't retain the power to germinate for very long, maybe two years.
[03:12.85]So there's actually quite a short window of opportunity for the seed to germinate. [03:17.25]So the shell somehow has to be broken down before this uh germination ability expires. [03:24.51]And... and then there’s a kind of rat that likes to feed on the seeds as well. [03:28.98]So, given all these limitations, not many seeds that the tree produces will actually germinate. [03:35.46]So this is a possible explanation for why the tree does not spread. [03:40.21]It doesn't necessarily explain how it became so rare but it explains why it doesn’t increase.
[03:46.64]OK, so it seems to be the case that this species, uh this Nightcap Oak, is not very good at spreading. [03:54.01]However, it seems, though we can't be sure, that it's very good at persisting as a population. [04:02.10]Uh, uh we, uh, there—there're some indications to suggest that the population of the Nightcap Oak has not declined over the last uh, y'know, many hundreds of years.
[04:14.38]So, it's stayed quite stable; [04:17.15]it—it's not a remnant of some huge population that has dwindled in the last few hundred years for some reason. [04:23.94]It’s not necessarily a species in retreat. [04:26.98]OK, so it cannot spread very well but it's good at maintaining itself. [04:32.71]It’s rare but it's not disappearing.
[04:35.85]OK the next thing we might wanna ask about a plant like that is what chances does it have to survive into the future. [04:44.00]Let's look at that.

6.Why does the professor say this?

你的答案:
正确答案:A
题目解析:
 后才能查看题目解析,还没有账号? 马上注册
(原文) They’re those little clusters sitting at the base of the leaves. Okay, what have we tried to find out about the tree since we’ve discovered it? Hum…or how…why is…is it so rare? That’s one of the first questi ons. Um… how is it…um…how does it reproduce? This’s another question. Um, maybe those two questions are actually related. 教授在提出两个问题后接着暗示的提问,会不会两者之间存在联系呢?也就是给学生们一个思考的方向,提示他们这两者间的联系是存在的,也就是希望学生们能由此想到。所以选 A。 其他 BC 为无关选项,D 完全与事实相反。

学习页面

Medi

terr

anean

加强 + 政府 + 名词后缀

加强的政府——管理

原文例句

加入生词

本文生词 0

色块区域是你收藏过的生词;

查询次数越多,颜色越深哦~

显示文中生词

登录后才能收藏生词哦,现在登录注册>

本文重点词 45

文中加粗单词为本文重点词;

根据词频与核心词范围精心挑选,托福考试必掌握词汇。

显示文中重点词
学习本文词汇

文中划选/双击的生词、加粗重点词已收纳至词盒

可随时点击词盒查看哦~

只有在词句精学模式下才能开启词盒功能哦~

我知道了

词盒
收藏
笔记
我的笔记
5000
保存
反馈