托福tpo5听力文本

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4 billion years, give or take a few hundred million years. But that‟s not very precise. If we had rock samples to study, we‟d know whether the small craters were formed by impacts during the final stages of plaary formation, or if they resulted from later meteor showers. Dian: But if we know around how old the Basin is, I‟m not sure that‟s reason enough to go to the Moon again. Professor: No…, but such crude estimates…um…we can do better than that. Besides, there are other things worth investigating, like is there water ice on the moon? Clementine‟s data indicated that the wall of the southpolar crater was more reflective than expected. So some experts think there‟s probably ice there. Also, data from a later mission indicates significant concentrations of hydrogen and by inference water less than a meter underground at both poles. Student: Well if there‟s water, how did it get there? Underground rivers? Professor: We think meteors that crashed into the moon or tails of passing ets may have introduced water molecules. Any water molecules that found their way to the floors of craters near the moon‟s poles, that water would be perpetually frozen, because the floors of those craters are always in shadow. Um…furthermore, if the water ice was mixed in with rock and dust, it would be protected from evaporation. Dian: So are you saying there might be primitive life on the moon? Professor: that‟s not my point at all. Um… ., say there is water ice on the moon. That would be a very practical value for a future moon base for astronauts. Water ice could be melted and purified for drinking. It could also be broken down into its ponent parts oxygen and hydrogen. Oxygen could be used to breathe, and hydrogen could be turned into fuel, rocket fuel. So water ice could enable the creation of a selfsustaining moon base someday, a mining camp perhaps or a departure point for further space exploration. Student: But holding tons of equipment to the moon to make fuel and build a life support system for a moon base, wouldn‟t that be too expensive? Professor: Permanent base, maybe a way‟s off, but we shouldn‟t have to wait for that. The dust at the bottom of the SPA Basin really does have a fascinating story to tell. I wouldn‟t give for a few samples of it. Conversation 2 Narrator Listen to a conversation between a student and a professor. Student Hi, I was wondering if I could talk with you about the assignment in the film theory class. Professor Of course, Jill. Student It seems that pretty much everyone else in the class gets what they are supposed to be doing but I‟m not so sure. Professor Well, the class is for students who are really serious about film. You must have taken film courses before. Student Yeah, in high school, film appreciation. Professor Um…I wouldn‟t think that would be enough. Did you concentrate mainly on form or content? Student Oh, definitely content. We‟d watch, say Lord of the Flies, and then discuss it. Professor Oh, that approach, treating film as literature, ignoring what makes it unique. Student I liked it, though. Professor Sure, but that kind of class. Well, I‟m not surprised that you are feeling a little lost. You know, we have two introductory courses that are supposed to be taken before you get to my course, one in film art, techniques, technical stuff and another in film history. So students in the class you are in should be pretty far along in film studies. In fact, usually the system blocks anyone trying to sign up for the class they shouldn‟t be taking. And who hasn‟t taken the courses you are required to do first as prerequisites. Student Well, I did have a problem with that but I discussed it with one of your office staff, and she gave me permission. Professor Of course. No matter how many times I tell them, they just keep on… Well, for your own good, I really suggest dropping back and starting at the usual place. Student Yes. But I‟ve already been in this class for 4 weeks. I‟d hate to just drop it now especially since I find it so different, so interesting. Professor I guess so. Frankly I can‟t believe you‟ve lasted this long. These are pretty indepth theories we‟ve been discussing and you‟ve been doing OK so far, I guess. But still, the program‟s been designed to progress through certain stages. Like any other professional training we build on pervious knowledge. Student Then maybe you could remend some extra reading I can do to… catch up? Professor Well, are you intending to study film as your main concentration? Student No, no. I am just interested. I‟m actually in marketing, but there seems to be a connection. Professor Oh…well, in…in that case, if you‟re taking the course just out of interest, I mean I still highly remend signing up for the introductory courses at so。