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新东方网为大家带来2020托福听力练习：嘈杂环境中青蛙发出视觉信号（下载），希望对大家有所帮助!更多内容请随时关注新东方网!
Ask anyone what sound a frog makes and they'll probably say ribbit.
But there's only one frog that makes that sound:the Pacific chorus frog.
It may have become the go-to frog call because it just happens to live near sound artists in Hollywood.
Herpetologists have long known that frog calls are more diverse than just ribbit.
But their communications are more diverse than just calls—they also signal each other by sight.
Say you're a male of a species called the Brazilian torrent frog.
And you live alongside a fast-flowing stream in the Amazon jungle.
You happily chirp away, advertising your availability to whatever female torrent frogs are around.
But when another male comes too close, your chirps give way to peeps and squeals.
So you wave your red and brown arm in front of your cream-colored face.
The ensuing color contrast turns your body into a warning light.
The intruder gets the hint and hops away to bother someone else.
Brazilian zoologist Fabio P. de Sa witnessed Brazilian torrent frogs using eighteen different visual displays, five of which had never been seen before in other frogs.
He and colleagues published their findings in the journal PLOS ONE.
The frog semaphore system probably developed because streams are noisy places.
Instead of shouting over the sound of rushing water, these frogs communicate by jumping, head bobbing, arm waving or even wagging their toes.
The set of signals is the most sophisticated ever documented for a frog, but de Sa thinks that other frogs could have similarly complex repertoires, if only researchers would take the time to look.
One thing is certain: it's not easy being green, but it's simple to be seen.
翻译见下页
如果你问别人青蛙的叫声是什么样，得到的答案可能会是呱呱声。但只有一种青蛙会发出这样的叫声，
那就是太平洋合唱哇。
由于碰巧居住在好莱坞的声音艺术家附近，因此这种青蛙的叫声就显得非常独特。
爬虫学家很早以前就已知晓青蛙的叫声不只呱呱，而且又多种多样的叫声。
但青蛙的交流方式除了叫声外还有多种形式—它们彼此之间也会通过发送信号进行交流。
假如你是一只雄性巴西湍蛙。
青蛙的信号.gif
而且你在亚马逊丛林激流边生活。
你对周围生活的雌性快乐的发出吸引的叫声。
但当其它雄性逐渐靠近，你的叫声马上变为唧唧尖叫。
这时你就在自己的奶白色脸前挥舞红褐色的手臂。
这种鲜明的对比色会将你的身体变成警示色。
收到这种讯号的入侵者就会跳走去打扰别人。
巴西动物学家法比奥·德萨就曾亲眼目睹巴西湍蛙使用18种不同的可视信息，而其中5种在其它青蛙中从未出现过。
他和同事们在《公共科学图书馆》杂志上发表了这项研究结果。
由于河流湍急，青蛙的信号系统可能会因此进化。
这些青蛙不再用嘹亮的歌声喊过湍急的河流，而是通过跳跃，晃动头部，摆动手臂或甚至摇摆脚趾等方式交流。
这种信号是蛙类研究中有记载以来最为复杂的方式，但德萨认为只要研究人员们肯花时间观察就会发现其它种类的青蛙或许有着同样复杂的行为方式。
而能够确认的一件事情是，变绿不易，但不难被发现。
1.happen to 偶然;发生
例句:If you happen to talk to him, have him call me.
如果你碰巧能和他说话，让他给我打个电话。
2.turn into 转化为;转变;变为
例句:I think I have got to stop or I might turn into a machine.
我想我得停下来了，否则我就会变成一台机器。
3.instead of 而不是
例句:The farmers will be paid for their grain in cash, instead of IOUs.
农民卖粮，将以现金支付，而不是白条了。
4.shout over 喊过
例句:The painest tear shout over graves after the words left unsaid and dids left undone.
最痛苦的泪水从坟墓里流出，为了还没有说过的话和还没做过的事。
以上是新东方网为大家带来的2020托福听力练习：嘈杂环境中青蛙发出视觉信号（下载），希望认真积极的备考，早日取得优异的成绩。更多内容请随时关注新东方网!
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