Official 24 Set 2

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  • Q3
  • Q4
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Crocodile Vocalization

纠错
  • Q1
  • Q2
  • Q3
  • Q4
  • Q5
  • Q6
What does the professor mainly discuss?
  • A. Factors that affect successful crocodile communication

  • B. Some reasons for crocodile vocalizations

  • C. Ways that newborn crocodiles learn to communicate

  • D. Reasons why crocodile vocalization is difficult to study

显示答案 正确答案: B

我的笔记 编辑笔记

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

    FEMALE PROFESSOR:OK, for today, let’s look at a reptile— a predator—that hasn’t evolved much in the last 70 million years.No discussion of reptiles would be complete without some mention of crocodiles.Now, we tend to think of crocodiles as uh, kind of solitary… hiding out in a swamp, kind of mysterious creatures...But we’re finding out that they aren’t as isolated as they seem.In fact, crocodiles interact with each other in a variety of ways.One way is with vocalizations… you know, sounds generated by the animal.This is true of the whole crocodile family which includes crocodiles themselves, alligators, etc…

    Take American alligators. If you were to go to a swamp during the breeding season, you’d hear a chorus of sounds. Deep grunts, hisses…These are sounds that male alligators make, and some of them are powerful enough to make the water vibrate.This sends a strong “go away” message to the other males, so the alligator can focus on sending other sound waves through the water… sound waves that you and I couldn’t even hear since they’re such low frequency.But they do reach the female alligator, who then goes to find, and mate with, the male.Vocalization is, um, well, it’s used for other reasons… like getting attention or dis—ah, letting others know that you’re distressed.

    Ah, let’s see… newborn crocodiles, or hatchlings, and their interactions with their mother.When they’re born, croc-baby crocodiles have a sort of muffled cry while they’re in their nest.Hatchlings are really vulnerable— especially to birds and small mammals—when they’re born, but their mother, who’s been keeping vigil nearby, hears their cry for help and carries them to safety… meaning, to water.So, she takes them out of the nest, ah, um, all the eggs hatch at once, so she has about 40 newborns to look after.She takes about 15 out of the nest at a time, carrying them in her mouth to the nearby water.While she’s taking one load of hatchlings, the others wait for her to come back, but do you think they’re quiet about it?No way!They’re clamoring for the mother’s attention, sort of squeaking, and practically saying, “Don’t forget about me!”I heard some great examples of this on a television program on crocodiles last week… anyone catch it?It had a few interesting bits, but you know…[concerned] uh, you have to be careful, think critically.Sometimes I don’t know where these shows find their [sarcastically] “experts.”

    MALE STUDENT:Excuse me. But um,does all that crying defeat the purpose? I mean, doesn’t it… attract more predators?

    FEMALE PROFESSOR:[thinking]Hmm, good question.I guess—well, I’m guessing that once the babies have the mother’s attention, they’re safe.She’s never too far away, an-and I think— I mean, would you mess with a mother crocodile?

    So, after the mother transports all the youngsters, they still call to each other, and to their mother.This communication continues right through to adulthood.Crocodiles have about 18 different sounds that they can make.There’s—uh, uh, you have deep grunting sounds, hisses, growls,squeaks, roars…So, there are many different sounds to interact or send messages.This is more typical of mammals than of reptiles…I mean, crocodiles’ brains are the most developed of any reptile… in that sense, they’re closer to mammals’ brains than other reptiles’ brains.And we know that mammals… ah, well dogs, for example… dogs vocalize many different sounds.Crocodiles have a similar level of, ah, vocal sophistication, if you will— which makes them unique among reptiles.

    Another thing would be, ah, if a hatchling gets separated from the rest of its family. Once the others get far enough away, its survival instinct kicks in.It’ll make a loud distress call, which its siblings answer… it calls again, and they continue calling back and forth until they all find each other again.

    Another thing, something that wasn’t on that TV show I mentioned— ah, mother crocodiles lead their young from one area to another, like when they have to find a different source of water.Usually she’ll lead them at night, when it’s safer for them, moving ahead and then letting out calls of reassurance so that they’ll follow her.Her voice helps give the babies the courage they need to leave the area and go someplace that’s a more desirable home for them.

  • 旁白:听下面一段生物课课堂上的讲解。

    教授:好的,今天我们来讲一种爬行动物,这种食肉动物在过去的七千万年中都没有进化多少。提到爬行动物就一定会谈到鳄鱼。现在我们通常认为鳄鱼是一种孤僻的动物,他们隐藏在沼泽中,令人感觉十分神秘。但是我们发现鳄鱼并不像大家想象的那样孤僻。实际上,鳄鱼之间的互动方式多种多样。其中一种就是发声法,也就是动物发出的声音。整个鳄鱼族类都是如此,包括短吻鳄等。

    例如美洲鳄。如果在繁殖季的沼泽中,你就会听到各种声音此起彼伏,低沉的咕噜声,嘶嘶声...这些声音都是雄鳄鱼发出的,有的声音强大到可以引起水的震动。这是向其他雄性鳄鱼发出走开的信号,这样它就可以专注的通过水来发出其他的声波,而由于这种声波的频率很低,我们大家都无法听到。但是雌鳄鱼可以接收到这种声音,找到并与雄鳄鱼交配。发声法也用于其他的原因,比如说引起注意,或者只是让其他鳄鱼知道他们很痛苦。

    比如说,新生的鳄鱼或刚孵出的小鳄鱼与母亲之间的沟通。当小鳄鱼刚出生的时候,他们会在巢穴中发出一种低沉的声音。刚孵化的小鳄鱼十分脆弱,尤其是面临鸟类和小型的哺乳动物的威胁,但是他们的妈妈在附近守夜,听到他们的叫声后,就会将他们转移到安全的地方,也就是水中。她将他们从巢中带出,卵是一起孵化的,所以母鳄鱼要照顾 40 只刚刚出生的小鳄鱼。她一次可以转移 15 只,将小鳄鱼放在她的嘴里带到附近的水中。当她将第一批新孵化的小鳄鱼送到水里时,其他的小鳄鱼就等待着她回来,但是你想他们会安静的等着妈妈回来吗?当然不会。他们大叫着引起妈妈的注意,尖叫着就像是说“别忘了还有我呢!”。上个星期我在电视上的一个有关鳄鱼的节目上看到了不少这样的例子。大家看到了吗?里面有几段非常有意思的画面,但是你看节目的时候要仔细,抱着审视的态度。有时候我真不知道他们是从哪里请的专家。

    学生:不好意思。那他们的叫声总能起到保护他们的作用吗?我是说,难道他们的叫声不会引起其他食肉动物的注意吗?

    教授:嗯,问得好。我想如果小鳄鱼引起了母鳄鱼的注意,他们就是安全的。母鳄鱼不会离开太远的。我的意思是,你会去惹一只母鳄鱼吗?

    当母鳄鱼将小鳄鱼都转移完毕,他们还会继续叫嚷,对其他的小鳄鱼还有他们的妈妈。这种交流一直会持续到他们成年后。鳄鱼能够发出 18 种不同的声音。有低沉的咕噜声,嘶嘶声,咆哮声,吱吱声,怒吼声...所以它们有许多不同的声音来交流或传递信息。相比爬行动物,哺乳动物的声音交流更具代表性。我的意思是,在爬行动物中鳄鱼的大脑是最发达的,在某种程度上,他们的大脑比其他爬行动物更接近哺乳动物。而据我们所知,哺乳动物,比如说狗,能发出许多种不同的声音。而鳄鱼的声音也很复杂,这使它在爬行动物中十分独特。

    还有一种情况,如果一只新生的鳄鱼离开了它家族的巢穴,一旦达到一定距离,它的生存本能就会发挥出来。它会发出很大的悲痛的叫声,如果它的兄弟姐妹听到了就会回应他,它就会继续叫,它们反复地叫,直到它们找到对方。

    还有另一种情况,是我提到的电视节目中没有提到的,当母鳄鱼带领小鳄鱼从一个地方转移到另一个地方,比如说它们要寻找另一处水源。通常它们会在夜里行动,因为这时相对比较安全,母鳄鱼在前面领路并发出使小鳄鱼安心的叫声,这样它们就会跟着母鳄鱼。她的声音会鼓励小鳄鱼,它们需要离开这个地方,去其他更适合它们生存的地方。

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    2 感谢 不懂
    音频1
    解析

    题型分析:主旨题

    原文定位Professor: OK. For today, let's look at a reptile, a predator that hasn't evolved much in the last seventy million years. No discussion of reptiles would be complete without some mention of crocodiles.

    Now, we tend to think of crocodiles as, uh, kind of solitary, hiding out in a swamp, uh, kind of mysterious creatures. But we are finding out that they aren't as isolated as they seem. In fact, crocodiles interact with each other in a variety of ways. One way is with vocalizations, you know, sounds generated by the animal. This is true of the whole crocodile family, which includes crocodiles themselves, alligators, etc.

    选项分析

    章前面一开始教授说到reptile 以及 crocodiles 随后but 引出 interact ways 然后着重讲解了vocalization.

    B选项即为文章核心关键词的原文定位, 是对全文主旨最准确的概括

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