T-cells托福聽力原文翻譯及問題答案

2023-05-29 16:28:18 來源：中國教育在線

T-cells托福聽力原文翻譯及問題答案

一、T-cells托福聽力原文：

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.”O(jiān)K?

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托福聽力中文翻譯：

旁白：在生物課上聽一節(jié)課的一部分。

女教授：這是對人類免疫系統(tǒng)的概述。但我們還有幾分鐘。有什么問題嗎？喬治？

男學(xué)生：是的。你說的是T細胞…“幼稚的T細胞”…你能再重復(fù)一遍嗎，還有…我們?yōu)槭裁催@么叫它們？

女教授：好的。它們被稱為T細胞，因為它們在胸腺中發(fā)育…

男學(xué)生：什么？

女教授：胸腺……那是T-H-Y-M-U-s。它是身體中的一個小器官。不管怎么說，這就是為什么我們這么叫它們——它們來自胸腺。T細胞是人體免疫系統(tǒng)的一部分。它們可以識別并清除體外可能導(dǎo)致疾病的細胞。

女學(xué)生：為什么“天真”？我的意思是，如果人們沒有足夠的經(jīng)驗來了解世界的危險，我們可能會說他們幼稚。

但是你怎么能說一個細胞“幼稚”

女教授：嗯，當這種免疫細胞遇到來自體外的細胞時……比如細菌…

它與這種細菌相互作用并學(xué)會識別它，因此，無論何時免疫細胞在未來遇到這種細菌，它都會攻擊并殺死它。在這一點上，我們稱之為“記憶T細胞”，因為它學(xué)會了識別識別這種特殊細菌的蛋白質(zhì)標記。但在學(xué)會從體外識別任何特定蛋白質(zhì)之前，我們稱之為“幼稚”好啊

女學(xué)生：是的，我明白了。

女教授：涉及到很多生物化學(xué)……我們將在下一節(jié)課中討論。但你的問題讓我想起了我的一些同事正在做的一項研究。它與熱量限制有關(guān)。

女生：卡路里？比如我們吃的食物中的卡路里？

女教授：沒錯。我們談?wù)摰氖翘恰⑻妓衔?、脂肪……我們身體燃燒以獲取能量……我們用卡路里來衡量。

好的，讓我們后退一點。

早在20世紀30年代，康奈爾大學(xué)的一位營養(yǎng)學(xué)家就嚴格限制老鼠的飲食。他給一組的每只老鼠減少30%的食物……或者更準確地說，比另一組的老鼠減少30%的卡路里，……而另一組的老鼠吃了正常量的食物。結(jié)果如何？喂食不足的老鼠比正常喂食的老鼠活得長得多。

男學(xué)生：哇，這只適用于老鼠嗎？

女教授：顯然不是；在從蛔蟲到。。。最近，恒河猴。

這兩組猴子得到了他們所需要的所有維生素、礦物質(zhì)和其他營養(yǎng)素，但其中一組的卡路里減少了30%?，F(xiàn)在，在一只猴子的平均壽命達到30年左右之后，很明顯，那些一直吃熱量限制飲食的猴子比那些我們認為是正常健康飲食的猴子做得要好得多。就血壓和許多其他指標而言，熱量受限的猴子更健康，它們只是看起來和行為都比“正常飲食”組的猴子年輕。而且，作為一個群體，他們活得更長。

男學(xué)生：很有趣，……但是有什么聯(lián)系呢？

女教授：哦，有免疫系統(tǒng)嗎？嗯，有研究表明，隨著動物年齡的增長，免疫系統(tǒng)的效率會降低，這在人類身上也是如此。我們認為這些幼稚的T細胞只是被耗盡了——我的意思是，身體并不是總是在制造很多新的T細胞。在一生中，隨著T細胞遇到越來越多的奇怪細菌或其他什么，這些幼稚的T細胞會變成記憶性T細胞。因此，在生命的后期，這些幼稚的T細胞越來越少，可以用來對付任何可能攻擊的新的致病微生物。這意味著免疫力下降，動物或人更容易生病。

但是熱量限制…這有點讓系統(tǒng)震驚，一個結(jié)果是…嗯，那些吃熱量限制飲食的猴子比你想象中那么大的猴子還剩下更多幼稚的T細胞。幼稚T細胞的預(yù)期下降顯然，熱量減少30%的沖擊確實減緩了這一速度。許多年后，由于仍保留著如此多的幼稚T細胞，這些猴子在抵御新感染方面比正常喂養(yǎng)的同齡、高齡猴子要好得多。

男學(xué)生：這就是為什么他們活得更長？

女教授：這一定是一個原因。不過，這一切都相當復(fù)雜……還有很多細節(jié)有待解決。

男學(xué)生：但是人類的結(jié)果是一樣的嗎？

女教授：很難說。一項好的研究需要幾十年的時間，要找到愿意參與的人并不容易。你愿意嗎？

男學(xué)生：少吃百分之三十？那太難了。

女教授：你肯定會的。

三、T-cells托福聽力問題：

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.