T-cells托福听力原文翻译及问题答案

2023-05-29 16:28:18 来源：中国教育在线

T-cells托福听力原文翻译及问题答案

一、T-cells托福听力原文：

NARRATOR:Listen to part of a lecture in a biology class.

FEMALE PROFESSOR:So that's the overview of the human immune system.But we have a few minutes left.Any questions?George?

MALE STUDENT:Yes.You talked about T cells…“naive T cells”…Can you go over that part again,and also…why do we call’em that,anyway?

FEMALE PROFESSOR:All right.They're-they're known as T cells because they develop in the thymus…

MALE STUDENT:The what?

FEMALE PROFESSOR:Thymus…that's T-H-Y-M-U-S.It's a small organ in the body.Anyway,that’s why we call'em that—they come from the thymus.And T cells are a part of the body's immune system.They can recognize and eliminate cells from outside the body that might cause disease.

FEMALE STUDENT:But why“naive”?I mean,we might call people naive if they don't have enough experience to know about…the dangers of the world.

But how can you call a cell“naive?”

FEMALE PROFESSOR:Well,when this type of immune cell encounters a cell from outside the body…like maybe a bacterium…

It interacts with that bacterium and learns to recognize it,so whenever the immune cell runs into that kind of bacterium in the future,it'll attack and kill it.At that point we call it a“memory T cell”because it's learned to recognize a protein marker that identifies this particular kind of bacterium.But before it's learned to recognize any particular protein from outside the body,we'd call it“naive.”OK?

FEMALE STUDENT:Yeah,I get it.

FEMALE PROFESSOR:There's a lot of biochemistry involved…that we'll get into in the next lecture.But your question reminds me about a study that some of my colleagues are doing.It relates to caloric restriction.

FEMALE STUDENT:Caloric?Like calories in the food we eat?

FEMALE PROFESSOR:Exactly.We’re talking about the sugars,carbohydrates,fats…that our bodies burn to get energy…which we measure in calories.

OK,let's back up a little.

Back in the 1930s,a nutritionist at Cornell University put mice on a severely restricted diet.He gave each mouse in one group 30 percent less food…or,more precisely,30 percent fewer calories than the mice in the other group,…which ate a normal amount.And the result?The underfed mice lived much longer than the normally fed ones.

MALE STUDENT:Wow,does that just go for mice?

FEMALE PROFESSOR:Apparently not. Similar results have come from experiments on other animals—from roundworms to...most recently,rhesus monkeys.

These monkeys—two groups of’em—were given all the vitamins and minerals and other nutrients they needed,except that one group got thirty percent fewer calories.And now,after thirty years or so—about an average lifetime for a monkey—it’s clear that the monkeys that have been on the calorie-restricted diet are doing a lot better than the ones on what we’d consider a normal healthful diet.Like,in terms of blood pressure and lots of other measures,the calorie-restricted monkeys are much healthier,and they just look and act younger than the monkeys in the“normal-diet”group.And,as a group,they're living longer.

MALE STUDENT:Interesting,…but what’s the connection?

FEMALE PROFESSOR:Oh,with the immune system?Well,it's been shown that the immune system becomes much less effective as animals age—that’s true in humans too.We think those naive T cells just get used up—I mean it's not like the body's always making lots of new ones.And over the course of a lifetime,as T cells encounter more and more strange bacteria or whatever,the naive T cells get turned into memory T cells.So,later on in life,there are fewer and fewer of these naive T cells left to deal with any new disease-causing organisms that might attack.Which means less immunity,and the animal—or person—is more likely to get sick.

But caloric restriction…it kinda shocks the system,and one result is…well,those monkeys on the calorie-restricted diet had lots more naive T cells left than you'd expect in monkeys that old.The expected drop in naive T cells—apparently,the shock of getting thirty percent fewer calories really slows that down.And after many years,with so many more naive T cells still in reserve,these monkeys are a lot better at fighting off new infections than normally fed monkeys of the same…advanced age.

MALE STUDENT:And that's why they live longer?

FEMALE PROFESSOR:Well,it's gotta be one reason.This is all pretty complex,though…with lots of details yet to be worked out.

MALE STUDENT:But are results the same for humans?

FEMALE PROFESSOR:Hard to say.A good study would take decades,and it's not easy finding people who'd want to take part.Would you?

MALE STUDENT:And eat thirty percent less?That'd be tough.

FEMALE PROFESSOR:You bet it would.

二、T-cells托福听力中文翻译：

旁白：在生物课上听一节课的一部分。

女教授：这是对人类免疫系统的概述。但我们还有几分钟。有什么问题吗？乔治？

男学生：是的。你说的是T细胞…“幼稚的T细胞”…你能再重复一遍吗，还有…我们为什么这么叫它们？

女教授：好的。它们被称为T细胞，因为它们在胸腺中发育…

男学生：什么？

女教授：胸腺……那是T-H-Y-M-U-s。它是身体中的一个小器官。不管怎么说，这就是为什么我们这么叫它们——它们来自胸腺。T细胞是人体免疫系统的一部分。它们可以识别并清除体外可能导致疾病的细胞。

女学生：为什么“天真”？我的意思是，如果人们没有足够的经验来了解世界的危险，我们可能会说他们幼稚。

但是你怎么能说一个细胞“幼稚”

女教授：嗯，当这种免疫细胞遇到来自体外的细胞时……比如细菌…

它与这种细菌相互作用并学会识别它，因此，无论何时免疫细胞在未来遇到这种细菌，它都会攻击并杀死它。在这一点上，我们称之为“记忆T细胞”，因为它学会了识别识别这种特殊细菌的蛋白质标记。但在学会从体外识别任何特定蛋白质之前，我们称之为“幼稚”好啊

女学生：是的，我明白了。

女教授：涉及到很多生物化学……我们将在下一节课中讨论。但你的问题让我想起了我的一些同事正在做的一项研究。它与热量限制有关。

女生：卡路里？比如我们吃的食物中的卡路里？

女教授：没错。我们谈论的是糖、碳水化合物、脂肪……我们身体燃烧以获取能量……我们用卡路里来衡量。

好的，让我们后退一点。

早在20世纪30年代，康奈尔大学的一位营养学家就严格限制老鼠的饮食。他给一组的每只老鼠减少30%的食物……或者更准确地说，比另一组的老鼠减少30%的卡路里，……而另一组的老鼠吃了正常量的食物。结果如何？喂食不足的老鼠比正常喂食的老鼠活得长得多。

男学生：哇，这只适用于老鼠吗？

女教授：显然不是；在从蛔虫到。。。最近，恒河猴。

这两组猴子得到了他们所需要的所有维生素、矿物质和其他营养素，但其中一组的卡路里减少了30%。现在，在一只猴子的平均寿命达到30年左右之后，很明显，那些一直吃热量限制饮食的猴子比那些我们认为是正常健康饮食的猴子做得要好得多。就血压和许多其他指标而言，热量受限的猴子更健康，它们只是看起来和行为都比“正常饮食”组的猴子年轻。而且，作为一个群体，他们活得更长。

男学生：很有趣，……但是有什么联系呢？

女教授：哦，有免疫系统吗？嗯，有研究表明，随着动物年龄的增长，免疫系统的效率会降低，这在人类身上也是如此。我们认为这些幼稚的T细胞只是被耗尽了——我的意思是，身体并不是总是在制造很多新的T细胞。在一生中，随着T细胞遇到越来越多的奇怪细菌或其他什么，这些幼稚的T细胞会变成记忆性T细胞。因此，在生命的后期，这些幼稚的T细胞越来越少，可以用来对付任何可能攻击的新的致病微生物。这意味着免疫力下降，动物或人更容易生病。

但是热量限制…这有点让系统震惊，一个结果是…嗯，那些吃热量限制饮食的猴子比你想象中那么大的猴子还剩下更多幼稚的T细胞。幼稚T细胞的预期下降显然，热量减少30%的冲击确实减缓了这一速度。许多年后，由于仍保留着如此多的幼稚T细胞，这些猴子在抵御新感染方面比正常喂养的同龄、高龄猴子要好得多。

男学生：这就是为什么他们活得更长？

女教授：这一定是一个原因。不过，这一切都相当复杂……还有很多细节有待解决。

男学生：但是人类的结果是一样的吗？

女教授：很难说。一项好的研究需要几十年的时间，要找到愿意参与的人并不容易。你愿意吗？

男学生：少吃百分之三十？那太难了。

女教授：你肯定会的。

三、T-cells托福听力问题：

Q1:1.What is the lecture mainly about?

A.The process by which immune cells are produced

B.The effects of consuming far fewer calories than usual

C.The function of an organ found in rhesus monkeys and in humans

D.The discovery of a nutrient necessary for good health

Q2:2.Why does the professor mention the thymus?

A.To explain how different types of food are turned into energy

B.To give an example of an organ attacked by certain bacteria

C.To introduce a research study by a nutritional biologist

D.To answer a question about certain immune cells

Q3:3.According to the professor,why are some cells called"naive"?

A.They originate from a relatively primitive type of cell.

B.They are easily eliminated by the immune system.

C.They are not yet able to recognize any particular protein marker.

D.They can become part of any one of various organs of the body.

Q4:4.In a recent study mentioned by the professor,what are two differences between the monkeys that have been fed a normal diet and the ones that have not?[Click on 2 answers]

A.The monkeys on a normal diet appear older.

B.The monkeys on a normal diet get sick less often.

C.The monkeys on a normal diet have fewer naive T cells.

D.The monkeys on a normal diet tend to live longer.

Q5:5.What does the professor think about a calorie-restricted diet?[Click on 2answers]

A.She would not find it easy to follow.

B.She is not sure humans would benefit from it

C.Doctors are not likely ever to recommend it for people.

D.It would probably affect humans differently than it affects monkeys.

Q6:6.What does the professor mean when she says this:

A.Problems in the study make its conclusions difficult to believe.

B.The actual effect on mice was not what it seemed.