North American Wood Frog托福聽力原文翻譯及問題答案

North American Wood Frog托福聽力原文翻譯及問題答案

一、North American Wood Frog托福聽力原文：

Narrator:Listen to part of a lecture in a biology class.Female Professor:Well,it's finally looking like spring is arriving—the last of the winter snow will be melting away in a few days.So before we close today,I thought I'd mention,uh,a biological event that's part of the transition from winter to spring…something you can go outside and watch,if you have some patience.There's a small creature that lives in this area—you've probably seen it:it's the North American wood frog…Now the wood frog’s not that easy to spot,since it stays pretty close to the ground,under leaves and things,and it blends in really well with its background,as you can see.But they’re worth the effort,because they do something very unusual—something you might not have even thought possible…OK,North American wood frogs live over a very broad territory,or range—they're found all over the northeastern United States,and all through Canada and Alaska—even inside the Arctic Circle.No other frog is able to live that far north.But wherever they live,once the weather starts to turn cold,and the temperatures start to drop below freezing—as soon as the frog even touches an ice crystal or a bit of frozen ground…well,it begins to freeze.Yes,Jimmy?You look a bit taken aback…Male Student:Wait…you mean,it's still alive,but it freezes?Solid?

Female Professor:Well,almost.Ice forms in all the spaces outside cells,but never within a cell.Male Student:But…then,how does its heart beat?

Female Professor:It doesn't.Male Student:But—how can it do…Female Professor:How can it do such a thing?Well,that first touch of ice apparently triggers a biological response inside the frog,that first of all starts drawing water away from the center of its body.So the middle part of the frog,its internal organs—its heart,lungs,liver—these start getting drier and drier,while the water that's being pulled away is forming a puddle around the organs,just underneath the skin.

And then that puddle of water starts to freeze.OK,up to now the frog's heart is still beating,right?Slower and slower,but….And in those last few hours before it freezes,it distributes glucose—a blood sugar—throughout its body,its circulatory system.Sort of acts like an antifreeze…

Male Student:A solution of antifreeze,like you put in your car in the winter?

Female Professor:Well,you tell me.In frogs,the extra glucose makes it harder for the water inside the cells to freeze,so the cells stay just slightly wet—enough so that they can survive the winter.Then after that,the heart stops beating altogether.So,is that the same?

Male Student:I don’t really know,but uh…h(huán)ow long does it stay that way?

Female Professor:Well,it could be days or even months—all winter,in fact.But,um,see,the heart really doesn't need to do any pumping now,because the blood is frozen too.Male Student:I just…I guess I just don't see how it isn't—y'know,clinically dead.Female Professor:Well,that's the amazing thing.And how it revives is pretty amazing too.After months without a heartbeat,springtime comes around again,the Earth starts to warm up,and suddenly one day—ping!A pulse—followed by another one,then another,until—maybe ten,twelve hours later,the animal is fully recovered.Male Student:And—does the,uh,thawing process have some kind of trigger as well?Female Professor:Well,we're not sure,actually.The peculiar thing is,even though the sun is warming the frog up on the outside,its insides thaw out first—the heart and brain and everything.But somehow,it all just happens that way every spring.

Male Student:And after they thaw?Does it affect them?Like their life span?Female Professor:Well,hmm…we really don't know a lot about how long a wood frog normally lives—probably just a few years.But there's no evidence that the freezing process affects its longevity.It does have some other impacts,though.In studies we've found that,when it comes to reproduction,freezing diminishes the mating performance of males:

after they’ve been frozen,and thawed of course,they don't seem quite as vocal,they move slower—and they seem to have a harder time recognizing a potential mate.So if a male frog could manage not to go through this freezing cycle,he'd probably have more success at mating.

二、North American Wood Frog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：看來春天終于來了，冬天的最后一場雪幾天后就會融化了。所以在我們今天結束之前，我想我應該提到，呃，一個生物學事件，它是從冬天到春天過渡的一部分……如果你有耐心的話，你可以到外面看。有一種小生物生活在這個地區(qū)，你可能見過它：它是北美林蛙……現(xiàn)在林蛙不那么容易被發(fā)現(xiàn)，因為它離地面很近，在樹葉和其他東西下面，而且它與背景很好地融合在一起，正如你所見。但是他們值得付出努力，因為他們做了一些非常不尋常的事情，你可能甚至沒有想到這是可能的……好吧，北美樹蛙生活在一個非常廣闊的領土上，或者說分布范圍很廣，它們遍布美國東北部，遍布加拿大和阿拉斯加，甚至在北極圈內。沒有其他青蛙能生活在那么遙遠的北方。但無論它們住在哪里，一旦天氣開始變冷，當青蛙接觸到冰晶或一小塊凍土時，溫度就開始降到零度以下……嗯，它開始結冰了。什么事，吉米？你看起來有點吃驚……男學生：等等……你是說，它還活著，但它凍結了？固體

女教授：嗯，差不多了。冰在細胞外的所有空間都會形成，但絕不會在細胞內形成。男學生：但是……那么，它的心跳是怎樣的？

女教授：不是。男學生：但它怎么能做……女教授：它怎么能做這樣的事？嗯，第一次接觸到冰顯然會觸發(fā)青蛙體內的生物反應，首先會將水從身體中心抽走。所以青蛙的中部，內臟，心臟，肺，肝臟開始變得越來越干燥，而被抽走的水在器官周圍，皮膚下面形成了一個水坑。

然后那灘水開始結冰。好吧，到目前為止，青蛙的心臟還在跳動，對嗎？越來越慢，但是…。在凍結前的最后幾個小時，它將葡萄糖（一種血糖）分配到全身和循環(huán)系統(tǒng)。有點像防凍劑…

男生：防凍液的解決方案，比如你在冬天把它放在車里？

女教授：好吧，你告訴我。在青蛙身上，額外的葡萄糖使細胞內的水更難凍結，因此細胞保持略微濕潤，這樣就可以在冬天存活下來。然后，心臟停止跳動。那么，這是一樣的嗎？

男學生：我真的不知道，但是，呃……這種情況會持續(xù)多久？

女教授：事實上，整個冬天可能是幾天甚至幾個月。但是，嗯，看，心臟現(xiàn)在真的不需要做任何泵送，因為血液也凍結了。男學生：我只是……我想我只是不明白為什么它不是——你知道，臨床死亡。女教授：好吧，這真是太神奇了。它是如何復蘇的，也非常令人驚訝。幾個月沒有心跳，春天又來了，地球開始變暖，突然有一天，砰砰！一個脈沖接著是另一個脈沖，然后是另一個脈沖，直到大約十、十二個小時后，動物完全康復。男學生：嗯，解凍過程也有某種觸發(fā)因素嗎？女教授：嗯，實際上我們不確定。奇怪的是，盡管太陽正在使青蛙的外部變暖，但它的內部首先融化了心臟、大腦和一切。但不知何故，每年春天都是這樣。

男學生：解凍后呢？這會影響他們嗎？比如他們的壽命？女教授：嗯……我們真的不太清楚一只林蛙通常能活多久，可能只有幾年。但沒有證據表明冷凍過程會影響其壽命。不過，它確實有其他一些影響。在研究中，我們發(fā)現(xiàn)，在生殖方面，冷凍會降低雄性的交配性能：

當然，在它們被冷凍、解凍后，它們的聲音似乎就不那么響亮了，它們的動作也變慢了，而且它們似乎很難識別出一個潛在的伴侶。因此，如果雄蛙能設法不經歷這種冰凍循環(huán)，那么它的交配可能會更成功。

三、North American Wood Frog托福聽力問題：

Q1:1.What is the main purpose of the lecture?

A.To explain the biological advantages of a physical change that occurs in North American wood frogs

B.To explain why the North American wood frog's habitat range has expanded

C.To describe the functioning of the circulatory system of the North American wood frog

D.To introduce students to an unusual phenomenon affecting North American wood frogs

Q2:2.Why does the professor first mention the arrival of spring?

A.To encourage students to look for thawing wood frogs

B.To point out the time period when frogs begin mating

C.To explain why the class will soon be doing experiments with wood frogs

D.To emphasize the speed of the thawing process

Q3:3.What happens to a wood frog as it begins to freeze?

A.Blood is concentrated in the center of its body.

B.Blood stops producing sugar.

C.Water moves out of its internal organs.

D.Water from just beneath the skin begins to evaporate.

Q4:4.What are two points the professor makes about the thawing process of the wood frog?[Click on 2 answers.]

A.The thawing process is not fully understood.

B.The thawing process takes longer than the freezing process.

C.The frog's internal organs thaw before its outer skin thaws.

D.Thawing occurs when the frog's heart begins pumping glucose through its body.

Q5:5.What impact does freezing have on some thawed wood frogs?

A.It increases their reproductive success.

B.It decreases their life span.

C.It causes them to be more vocal and active.

D.It reduces their ability to recognize potential mates.

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

A.She wants the student to clarify his question.

B.She wants the student to draw his own conclusions.

C.She thinks the student does not understand how car antifreeze works.

D.She thinks the student has misunderstood her point.

四、North American Wood Frog托福聽力答案：

A1:正確答案：D

A2:正確答案：A

A3:正確答案：C

A4:正確答案：AC

A5:正確答案：D

A6:正確答案：B

>> 雅思 托福 免費測試、量身規(guī)劃、讓英語學習不再困難<<