托福听力_考前小试牛刀（四）

TPO12听力文本

Conversation 1

Narrator

Listen to a conversation between a student and a professor.

Student

So Professor Tibets, your notes said that you want to see me about my heavy-weight paper. I have to say that grade wasn’t what I was expecting. I thought I’d done a pretty good job.

Professor

Oh, you did. But do you really want to settle for pretty good when you can do something very good?

Student

You think it can be very good?

Professor

Absolutely!

Student

Would that mean you’d…I could get a better grade?

Professor

Oh, sorry! It’s not for your grade. It's…I think you could learn a lot by revising it.

Student

You mean, rewrite the whole thing? I really swamped. There’re deadlines wherever I turn and… and I don’t really know how much time I could give it.

Professor

Well, it is a busy time, with spring break coming up next week. It’s your call. But I think with all a little extra effort, you could really turn this into a fine essay.

Student

No… yeah…I mean, after I read your comments, I...I can see how it tries to do too much.

Professor

Yeah. It’s just too ambitious for the scope of the assignment.

Student

So I should cut out the historical part?

Professor

Yes. I would just stick to the topic. Anything unrelated to the use of nature EMITRY has no place in the paper. All that tangential material just distracted from the main argument.

Student

Yeah, I never know how much to include. You know…where to draw the line?

Professor

Tell me about it! All writers struggled without one. But it’s something you can learn. That will become more clear with practice. But I think if you just cut out the…emm…

Student

The stuff about history, but if I cut out those sections, won’t it be too short?

Professor

Well, better a short well-structured paper than a long paper that poorly-structured and wanders off topic.

Student

So all I have to do is to leave those sections?

Professor

Well, not so fast. After you cut out those sections, you’ll have to go back and revise the rest, to see how it all fits together. And of course, you’ll have to revise the introduction too, to accurately describe what you do in the body of the paper. But that shouldn’t be too difficult. Just remember to keep the discussion focused. Do you think you can get it to me by noon tomorrow?

Student

Wow…emm…I have so much…er…but I’ll try.

Professor

OK, good! Do try! But if you can’t, well, sure for after spring break, OK?

【Lecture 1】

Biology

Narrator

Listen to part of a lecture in a Biology Class.

Professor

As we learn more about the DNA in human cells and how it controls the growth and development of cells, then maybe we can explain a very important observation, that when we try to grow most human cells in libratory, they seem programmed to divide only a certain number of times before they die. Now this differs with the type of cell. Some cells, like nerve cells, only divide seven to nine times in their total life. Others, like skin cells, will divide many, many more times. But finally the cells stop renewing themselves and they die. And in the cells of the human body itself, in the cells of every organ, of almost every type of tissues in the body, the same thing will happen eventually.

OK, you know that all of persons’ genetic information is contained on very long pieces of DNA called Chromosomes. 46 of them are in the human cells that’s 23 pairs of these Chromosomes are of very lengths and sizes. Now if you look at this rough drawing of one of them, one Chromosome is about to divide into two. You see that it sort of looks like, well actually it’s much more complex than

this but it reminds us a couple of springs linked together to coil up pieces of DNA. And if you stretch them out you will find they contain certain genes, certain sequences of DNA that help to determine how the cells of the body will develop. When researchers look really carefully at the DNA in Chromosomes though, they were amazed, we all were, to find that only a fraction of it, maybe 20-30%, converts into meaningful genetic information. It’s incredible; at least it was to me. But if you took away all the DNA that codes for genes, you still have maybe 70% of the DNA left over. That’s the so-called JUNK DNA. Though the word junk is used sort of townies cheek. The assumption is that even these DNA doesn’t make up any of the genes it must serve some other purpose. Anyway, if we examine these ends of these coils of DNA, we will find a sequence of DNA at each end of every human Chromosome, called a telomere. Now a telomere is a highly repetitious and genetically meaningless sequence of DNA, what we were calling JUNK DNA. But it does have any important purpose; it is sort of like the plastic tip on each end of shoelace. It means not help you tie your shoe but that little plastic tip keeps the rest of the shoelace, the shoe string from unraveling into weak and useless threads. Well, the telomere at the end of Chromosomes seems to do about the same thing--- protect the genes the genetically functional parts of the Chromosome from being damaged. Every time the Chromosome divides, every time one cell divides into two. Pieces of the ends of the Chromosome, the telomere, get broken off. So after each division, the telomere gets shorter and one of the things that may happen after a while is that pieces of the genes themselves get broken off the Chromosomes. So the Chromosome is nowlosing important genetically information and is no longer functional. But as long as the telomeres are at certain length they keep this from happening. So it seems that, when the, by looking at the length of the telomeres on specific Chromosomes we can actually predict pretty much how long certain cells can successfully go on dividing. Other some cells just seem to keep on dividing regardless which mean not be always a good thing if it gets out of control. But when we analyze the cells chemically we find something very interesting, a chemical in them, and an enzyme called telomerase. As bits of the telomere break off from the end of Chromosome, this chemical, this telomerase can rebuild it, can help resemble the protected DNA, the telomere that the Chromosome is lost. Someday we may be able to take any cell and keep it alive functioning and reproducing itself essentially forever through the use of telomerase. And in the future we may have virtually immortal nerve cells and immortal skin cells of whatever because of these chemical, telomerase can keep the telomere on the ends of Chromosomes from getting any shorter.

【Lecture 2】

Business

Narrator

Listen to part of a lecture in a Business Class

Professor

Ok, as we’ve talked about a key aspect of running a successful business is knowing, um, getting a good sense of what the customer actually wants, and how they perceive your product. So with that in mind, I want to describe a very simple method of researching customer preference, and it is becoming increasingly common, it's called----MBWA----which stands for managing bywandering around. Now, MBWA, that's not the most technical sounding name you've ever heard, but it describes the process pretty accurately. Here is how it works.

Basically, Um, the idea is that business owners or business managers just go out and actually talk to their customers, and learn more about how well the business is serving their needs, and try to see what the customer experiences, because that's a great way to discover for yourself, how your product is perceived, what the strengths and weaknesses are, you know, how to you can improved it that sort of thing, you know Dortans, they make soup and can vegetables and such. Well, the head of the company, had Dortans’ topped executives walk around supermarkets, um, asking shoppers what they thought of Dortans’ soup, and he use the data to make changes to the company's product, I mean, when Dortans of all the companies, embraces something as radical as MBWA, it really show you how popular the theory has become, yes, Lisa?

Student A

But this is dangerous to base decisions on information from a small sample of people? Is it large scale market research safer getting data on a lot of people?