『新东方在线托福听力』为托福考生准备了ETS托福TPO/Official 17 Passage 2阅读练习，TPO/Official 17 Passage 2原文答案解析，TPO/Official 17 Passage 2阅读原文练习音频翻译。

托福TPO/Official 17 Passage 2阅读原文题目答案及解析-新东方托福官方网校手机版

森林白天的光线质量随植被的密度、太阳的角度和天空中云的数量而变化。

The daytime quality of light in forests varies with the density of the vegetation, the angle of the Sun, and the amount of cloud in the sky.

动物和植物在不同的光照条件下都有不同的外观。

Both animals and plants have different appearances in these various lighting conditions.

一种颜色或图案在一种光中相对不明显，但在另一种光中可能很明显。

A color or pattern that is relatively indistinct in one kind of light may be quite conspicuous in another.

在森林多变且不断变化的光环境中，动物必须能够向自己物种的成员发送视觉信号，同时避免被捕食者发现。

In the varied and constantly changing light environment of the forest, an animal must be able to send visual signals to members of its own species and at the same time avoid being detected by predators.

动物可以通过选择让自己的图案最不明显的光线环境来躲避捕食者。

An animal can hide from predators by choosing the light environment in which its pattern is least visible.

这可能需要在一天中不同的时间或在不同的天气条件下移动到森林的不同部分，也可能通过根据光线条件的变化改变颜色来实现。

This may require moving to different parts of the forest at different times of the day or under different weather conditions, or it may be achieved by changing color according to the changing light conditions.

许多种类的两栖动物（青蛙和蟾蜍）和爬行动物（蜥蜴和蛇）能够改变它们的颜色图案来伪装自己。

Many species of amphibians (frogs and toads) and reptiles (lizards and snakes) are able to change their color patterns to camouflage themselves.

有些还通过改变颜色来发出信号。

变色龙蜥蜴有最惊人的能力做到这一点。

The chameleon lizard has the most striking ability to do this.

有些种类的变色龙在几秒钟内就能从一种相当单调的外表变成五彩缤纷的狂欢色彩。

Some chameleon species can change from a rather dull appearance to a full riot of carnival colors in seconds.

通过这种方式，它们表明了自己的攻击性或交配意愿。

By this means, they signal their level of aggression or readiness to mate.

其他物种考虑到光的变化条件，只在光线适宜时才进行视觉展示。

Other species take into account the changing conditions of light by performing their visual displays only when the light is favorable.

一只雄性天堂鸟可能通过在最佳的舞台环境中展示他壮观的羽毛来吸引雌性，从而使自己成为人们关注的焦点。

A male bird of paradise may put himself in the limelight by displaying his spectacular plumage in the best stage setting to attract a female.

某些蝴蝶飞进阳光照射到的森林地面上，在明亮的聚光灯下张开和合上它们美丽的图案翅膀。

Certain butterflies move into spots of sunlight that have penetrated to the forest floor and display by opening and closing their beautifully patterned wings in the bright spotlights.

它们也互相竞争获得最好的阳光。

They also compete with each other for the best spot of sunlight.

在雨林中，很少有光透过树冠和树枝到达地面——或者接近地面——在这些层面上，黄绿色的波长占主导地位。

Very little light filters through the canopy of leaves and branches in a rain forest to reach ground level—or close to the ground—and at those levels the yellow-to-green wavelengths predominate.

如果一个信号是最亮的，它可能是最容易被看到的。

A signal might be most easily seen if it is maximally bright.

在森林最低层的绿到黄的光照条件下，黄色和绿色是最亮的颜色，但当动物发出信号时，如果动物坐在黄或绿背景的区域，这些颜色就不是很明显。

In the green-to-yellow lighting conditions of the lowest levels of the forest, yellow and green would be the brightest colors, but when an animal is signaling, these colors would not be very visible if the animal was sitting in an area with a yellowish or greenish background.

最好的信号不仅取决于它的亮度，还取决于它与背景的对比度。

The best signal depends not only on its brightness but also on how well it contrasts with the background against which it must be seen.

因此，在这部分雨林中，红色和橙色是最好的信号颜色，它们也是澳大利亚丛林火鸡在地面行走时发出信号的颜色。

In this part of the rain forest, therefore, red and orange are the best colors for signaling, and they are the colors used in signals by the ground-walking Australian brush turkey.

这种动物生活在澳大利亚东海岸的热带雨林和灌木丛中，有从棕色到黑色的羽毛，头颈处的皮肤是赤红色的，颈部有一条领带状的橙黄色条纹，松松地垂着。

This species, which lives in the rain forests and scrublands of the east coast of Australia, has a brown-to-black plumage with bare, bright-red skin on the head and neck and a neck collar of orange-yellow loosely hanging skin.

在求偶和攻击性展示期间，火鸡通过膨胀颈部区域的囊来扩大它的彩色颈圈，然后它会摆动下垂的彩色信号装置部分，并发出吸引或排斥的叫声。

During courtship and aggressive displays, the turkey enlarges its colored neck collar by inflating sacs in the neck region and then flings about a pendulous part of the colored signaling apparatus as it utters calls designed to attract or repel.

这一令人印象深刻的展示在照亮森林地面的光谱中清晰可见。

This impressive display is clearly visible in the light spectrum illuminating the forest floor.

生活在热带雨林中色彩较淡的鸟类和动物往往依赖于视觉以外的信号形式，尤其是长距离的信号。

Less colorful birds and animals that inhabit the rain forest tend to rely on forms of signaling other than the visual, particularly over long distances.

犀鸟刺耳的叫声和不会被认错的长臂猿叫声是东南亚雨林的特征。

The piercing cries of the rhinoceros hornbill characterize the Southeast Asian rain forest, as do the unmistakable calls of the gibbons.

在树木茂密的环境中，声音是远距离交流的最佳方式，因为与光相比，它几乎不受树木和其他植被的阻碍。

In densely wooded environments, sound is the best means of communication over distance because in comparison with light, it travels with little impediment from trees and other vegetation.

在森林里，视觉信号只能在很短的距离内被看到，因为没有树木的阻挡。

In forests, visual signals can be seen only at short distances, where they are not obstructed by trees.

雄性风鸟在求爱时同时利用这两种信号模式。

The male riflebird exploits both of these modes of signaling simultaneously in his courtship display.

每只翅膀被打开时发出的声音都能传得很远，并广泛地宣传他的存在。

The sounds made as each wing is opened carry extremely well over distance and advertise his presence widely.

当雌性靠近时，仪式化的视觉展示在近距离内进行交流。

The ritualized visual display communicates in close quarters when a female has approached.

The word “conspicuous” in the passage is closest in meaning to

According to paragraph 2, what is problematic about an animal’s sending visual signals to members of its own species?

According to paragraph 2, all of the following are reasons amphibians and reptiles change color EXCEPT

According to paragraph 3, butterflies move into spots of sunlight in order to

According to paragraph 4, what is true about light that reaches ground level?

Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

Which of the following can be inferred from paragraph 4 about yellow and green colors compared with red and orange colors at the bottom of the forest?

What can be inferred from paragraph 5 about the less colorful birds and animals that inhabit the forest?

Look at the four squares  that indicate where the following sentence could be added to the passage. There is also the long, rather terrifying call of the male orangutan, which carries over considerable distances to advertise his presence.  Where would the sentence best fit? Click on a square  to add the sentence to the passage.

Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

Animal Signals in the Rain Forest The daytime quality of light in forests varies with the density of the vegetation, the angle of the Sun, and the amount of cloud in the sky. Both animals and plants have different appearances in these various lighting conditions. A color or pattern that is relatively indistinct in one kind of light may be quite conspicuous in another. In the varied and constantly changing light environment of the forest, an animal must be able to send visual signals to members of its own species and at the same time avoid being detected by predators. An animal can hide from predators by choosing the light environment in which its pattern is least visible. This may require moving to different parts of the forest at different times of the day or under different weather conditions, or it may be achieved by changing color according to the changing light conditions. Many species of amphibians (frogs and toads) and reptiles (lizards and snakes) are able to change their color patterns to camouflage themselves. Some also signal by changing color. The chameleon lizard has the most striking ability to do this. Some chameleon species can change from a rather dull appearance to a full riot of carnival colors in seconds. By this means, they signal their level of aggression or readiness to mate. Other species take into account the changing conditions of light by performing their visual displays only when the light is favorable. A male bird of paradise may put himself in the limelight by displaying his spectacular plumage in the best stage setting to attract a female. Certain butterflies move into spots of sunlight that have penetrated to the forest floor and display by opening and closing their beautifully patterned wings in the bright spotlights. They also compete with each other for the best spot of sunlight. Very little light filters through the canopy of leaves and branches in a rain forest to reach ground level—or close to the ground—and at those levels the yellow-to-green wavelengths predominate. A signal might be most easily seen if it is maximally bright. In the green-to-yellow lighting conditions of the lowest levels of the forest, yellow and green would be the brightest colors, but when an animal is signaling, these colors would not be very visible if the animal was sitting in an area with a yellowish or greenish background. The best signal depends not only on its brightness but also on how well it contrasts with the background against which it must be seen. In this part of the rain forest, therefore, red and orange are the best colors for signaling, and they are the colors used in signals by the ground-walking Australian brush turkey. This species, which lives in the rain forests and scrublands of the east coast of Australia, has a brown-to-black plumage with bare, bright-red skin on the head and neck and a neck collar of orange-yellow loosely hanging skin. During courtship and aggressive displays, the turkey enlarges its colored neck collar by inflating sacs in the neck region and then flings about a pendulous part of the colored signaling apparatus as it utters calls designed to attract or repel. This impressive display is clearly visible in the light spectrum illuminating the forest floor. Less colorful birds and animals that inhabit the rain forest tend to rely on forms of signaling other than the visual, particularly over long distances.  The piercing cries of the rhinoceros hornbill characterize the Southeast Asian rain forest, as do the unmistakable calls of the gibbons.  In densely wooded environments, sound is the best means of communication over distance because in comparison with light, it travels with little impediment from trees and other vegetation.  In forests, visual signals can be seen only at short distances, where they are not obstructed by trees.  The male riflebird exploits both of these modes of signaling simultaneously in his courtship display. The sounds made as each wing is opened carry extremely well over distance and advertise his presence widely. The ritualized visual display communicates in close quarters when a female has approached.