tpo6listening听力文本

tpo6listening听力文本内容摘要：

‟s another question. Um, maybe those two questions are actually related. Jim? Student Hum …I don‟t know. But I can imagine that…for instance, seed disposal might be a factor. I mean if the…er…you know, if the seeds cannot really dis perse in the wild area, then, you know, the tree may not colonize new areas. It can‟t spread from the area where it‟s growing. Professor Right. That‟s…that‟s actually a very good answer. Um, of course, you might think there might not be any areas where the tree could spread into, er…because…um…well, it‟s very specialized in terms of the habitat. But, that‟s not really the case here. Um…the suitable habitat, that is, the actual rainforest is much larger than the few hectares where the Nightcap Oak grows. Now this tree is a flowering tree as I showed you. Um…um…it produces a fruit, much like a plum. On the inci…inside there‟s a seed with a hard shell. It…it appears that the shell has to crack open or break down somewhat to allow the seed to soak up water. You know, if the Nightcap Oak remains…if their seeds remain locked inside their shell, they will not germinate . Actually, the seeds…er…they don‟t retain the power to germinate for very long, maybe two years. So there‟s actually quite a short window of opportunity for the seed to germinate. So the shell somehow has to be broken down before this…um…germination ability expires. And…and then there‟s a kind of rat that likes to feed on the seeds as well. So, given all these limitations, not many seeds that the tree produces will actually germinate. So this is a possible explanation for why the tree does not spread. It doesn‟t necessarily explain how it became so rare, but it explains why it doesn‟t increase. OK, so it seems to be the case that the species, this Nightcap Oak is not very good at spreading. However, it seems, though we can‟t be sure, that it‟s very good at persisting as a population. Um…we…there‟s some indications to suggest that the population of the Nightcap Oak has not declined over the last er…you know, many hundreds of years. So it‟s stayed quite stable. It‟s not a remnant of some huge population that is dwindled in last few hundred years for some reason. It‟s not necessarily a species in retreat. Ok, so it cannot spread very well, but it‟s good at maintaining itself. It‟s rare, but it‟s not disappearing. Ok, the next thing we might want to ask about the plant like that is what chances does it have to survive into the future. Let‟s look at that. Conversation Narrator Listen to a conversation between a student and a professor. Student Professor Martin? Professor Uh, hi, Lisa, what can I do for you? Student Well, I‟ve been thinking about, you know, what you were saying in class last week, about how we shouldn‟t wait until the last minute to find an idea and get started working on our term paper. Professor Good, good, and have you e up with anything? Student Well, yeah, sort of. See, I‟ve never had a linguistics class before, so I was sort of, I mean, I was looking over the course description and a lot of the stuff you described there, I just don‟t know what it is talking about, you know, or what it means. But there was one thing that really did jump out at me Professor Yes? Student The section on dialects, cos…like, t hat‟s the kind of thing that‟s always sort of intrigued me, you know? Professor Well, that‟s certainly an interesting topic. But you may not realize, I mean, the scope... Student Well, especially now, cos I‟ve got like one roommate who is from the south and another one from New York. And we all talk like totally different, you know? Professor Yes, I understand. But… Student But then I was noticing, like, we don‟t really get into this till the end of the semester, you know. So I… Professor So, you want some pointers where to go for information on the subject? Well, you could always start by reading the chapter in the book on social linguistics. That will give you a basic understanding of the key issues involved here. Student Yeah, that‟s what I thought. So I started reading the chapter, you know, about how everyone speaks some dialect of a language. And I‟m wondering like, well, how do we even manage to understand each other at all? Professor Ah, yes, an interesting question. You see… Student So then I read the part about dialect acmodation. You know, the idea that people tend to adapt their speaking to make it closer to the speech of whomever they‟re talking to, and I‟m thinking, yeah, I do that when I talk with my roommates, and without even thinking about it or anything, you know. Professor OK, all right. Dialect acmodation is a more manageable sort of topic. Student So I was thinking like, I wonder just how much other people do the same thing. I mean, there are students here。