『新东方在线托福阅读』为托福考生准备了ETS托福TPO/Official 11 Passage 2阅读练习：According to paragraph 5, how did the birds fly when the real Sun was visible?真题题目及答案解析，TPO/Official 11 Passage 2阅读原文范文音频翻译

托福TPO/Official 11 Passage 2阅读原文According to paragraph 5, how did the birds fly when the real Sun was visible?题目答案及解析-新东方托福官方网校手机版

对于南美而言，知更鸟是一种每年春天都会飞往北方的鸟。

To South Americans, robins are birds that fly north every spring.

对于北美而言，知更鸟是每年的冬天会在南方度过一个简单的假期。

To North Americans, the robins simply vacation in the south each winter.

除此之外，它们会飞到南美特定的地方，并且经常在下一个春天飞回到北美同样的树界范围内。

Furthermore, they fly to very specific places in South America and will often come back to the same trees in North American yards the following spring.

问题不是为什么它们会离开寒冷的冬天，而是它们是怎样找到迁徙的路径的。

The question is not why they would leave the cold of winter so much as how they find their way around.

这个问题困惑了人们很多年，直到20世纪50年代，一个叫古斯塔夫克莱默的德国科学家提供了一些解答，同时在这个过程中也产生出了新的疑问。

The question perplexed people for years, until, in the 1950’s, a German scientist named Gustave Kramer provided some answers and, in the process, raised new questions.

克莱默开展了重要的新的关于动物如何定位和导航的研究。

Kramer initiated important new kinds of research regarding how animals orient and navigate.

定位仅仅就是朝着对的方向，而导航包括了找到从A到B的路径。

Orientation is simply facing in the right direction; navigation involves finding one’s way from point A to point B.

在克莱默的早期研究里，他发现在本该鸟要迁徙的那段时间，笼子里的鸟会变的非常焦躁不安。

Early in his research, Kramer found that caged migratory birds became very restless at about the time they would normally have begun migration in the wild.

除此之外，他发现在这些鸟在笼子里面拍打翅膀的时候，它们经常会朝着平时迁移路径的方向飞。

Furthermore, he noticed that as they fluttered around in the cage, they often launched themselves in the direction of their normal migratory route.

然后他用笼子里的八哥做了实验，并且发现事实上，除了在天空多云的时候外，它们移动的方向正是迁徙的方向，在天空多云时它们的焦躁不安的移动是没有清晰的方向的。

He then set up experiments with caged starlings and found that their orientation was, in fact, in the proper migratory direction except when the sky was overcast, at which times there was no clear direction to their restless movements.

因此克莱默推测，它们是根据太阳的位置来移动的。

Kramer surmised, therefore, that they were orienting according to the position of the Sun.

为了验证这一想法，他挡住了它们对太阳的视线，并用镜子改变了太阳的视位置。

To test this idea, he blocked their view of the Sun and used mirrors to change its apparent position.

他发现在这些情况下，鸟会根据新的“太阳”来移动。

He found that under these circumstances, the birds oriented with respect to the new “Sun.”

看上去鸟类是利用太阳作为指南针来确定方向的。

They seemed to be using the Sun as a compass to determine direction.

在那个时候，这个想法听上去很荒唐。

At the time, this idea seemed preposterous.

我们有些人有了地图还会迷路，鸟怎么会可能用太阳来导航呢？

How could a bird navigate by the Sun when some of us lose our way with road maps?

很明显，接下来还需要更多的试验。

所以，在另外一组实验中，克莱默在笼子旁边放了几个一模一样的食物盒子，其中只有一个盒子里面有食物。

So, in another set of experiments, Kramer put identical food boxes around the cage, with food in only one of the boxes.

所有盒子的位置都是不变的，而且装有食物的那个盒子始终置于罗盘的同一个方向。

The boxes were stationary, and the one containing food was always at the same point of the compass.

然而，它相对于周围环境的位置可以通过旋转容纳鸟类的内笼或作为背景的外墙来改变。

However, its position with respect to the surroundings could be changed by revolving either the inner cage containing the birds or the outer walls, which served as the background.

只要是鸟可以看得到太阳，无论是周围环境怎么变化，它们都可以准确地找出那个装有食物的盒子。

As long as the birds could see the Sun, no matter how their surroundings were altered, they went directly to the correct food box.

无论是这个盒子在右面墙壁还是左面墙壁的前方，它们都一点也不困惑。

Whether the box appeared in front of the right wall or the left wall, they showed no signs of confusion.

但是在多云的天气，鸟就会迷失方向，很难定位到那个盒子。

On overcast days, however, the birds were disoriented and had trouble locating their food box.

在人工太阳的实验里，克莱默又有了另一个有趣的发现。

In experimenting with artificial suns, Kramer made another interesting discovery.

如果人工太阳位置保持不变，这些鸟会以每小时15度角的速度改变它们的方向，而这正好是太阳在天空中运行的速度。

If the artificial Sun remained stationary, the birds would shift their direction with respect to it at a rate of about 15 degrees per hour, the Sun’s rate of movement across the sky.

很明显，这些鸟会认为它们看到的那个“太阳”是以那个速度移动的。

Apparently, the birds were assuming that the “Sun” they saw was moving at that rate.

但是，当真正的太阳清晰可见时，它们却保持了固定的方向，正如太阳在天空中移动一样。

When the real Sun was visible, however, the birds maintained a constant direction as it moved across the sky.

换句话说，它们能够去适应太阳的移动。

In other words, they were able to compensate for the Sun’s movement.

这意味着某种生物钟在运行，而且是很精确的生物钟。

This meant that some sort of biological clock was operating–and a very precise clock at that.

或许它们是通过夜晚的天空导航的。

为了论证这个想法，在鸟类的迁徙期，夜间迁徙的笼子里的鸟被放在天文馆地板上。

To test the idea, caged night-migrating birds were placed on the floor of a planetarium during their migratory period.

这个天文馆事实上上是一个剧场，穹顶状的天花板可以投射出一年所有夜晚的景象。

A planetarium is essentially a theater with a domelike ceiling onto which a night sky can be projected for any night of the year.

当天文馆里面形成的夜晚和外面一致时，鸟就会朝着它们平时迁徙的方向拍打翅膀。

When the planetarium sky matched the sky outside, the birds fluttered in the direction of their normal migration.

但是当穹顶旋转时，鸟就会改变它们的方向来适应人造天空。

But when the dome was rotated, the birds changed their direction to match the artificial sky.

这很清楚地表明这些鸟是通过星宿位置来定位的。

The results clearly indicated that the birds were orienting according to the stars.

越来越多的证据表明，鸟是通过多种多样的环境线索来导航的。

There is accumulating evidence indicating that birds navigate by using a wide variety of environmental cues.

其他的研究领域也包括磁场、地标、海岸线、声波甚至气味。

Other areas under investigation include magnetism, landmarks, coastlines, sonar, and even smells.

这些研究非常的复杂，因为数据有时会自相矛盾并且很显然物理过程会随着时间发生变化。

The studies are complicated by the fact that the data are sometimes contradictory and the mechanisms apparently change from time to time.

另外，一种感知能力可能会支持另一种。

Furthermore, one sensory ability may back up another.

Which of the following can be inferred about bird migration from paragraph 1?

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.

According to paragraph 3, why did Kramer use mirrors to change the apparent position of the Sun?

According to paragraph 3, when do caged starlings become restless?

Which of the following can be inferred from paragraph 4 about Kramer’s reason for filling one food box and leaving the rest empty?

According to paragraph 5, how did the birds fly when the real Sun was visible?

The experiment described in paragraph 5 caused Kramer to conclude that birds possess a biological clock because

According to paragraph 6, how did the birds navigate in the planetarium’s nighttime environment?

Which of the following best describes the author’s presentation of information in the passage?

Look at the four squares  that indicate where the following sentence could be added to the passage. He arranged the feed boxes at various positions on a compass.  Where would the sentence best fit? Click on a square  to add the sentence to the passage.

Orientation and Navigation To South Americans, robins are birds that fly north every spring. To North Americans, the robins simply vacation in the south each winter. Furthermore, they fly to very specific places in South America and will often come back to the same trees in North American yards the following spring. The question is not why they would leave the cold of winter so much as how they find their way around. The question perplexed people for years, until, in the 1950’s, a German scientist named Gustave Kramer provided some answers and, in the process, raised new questions. Kramer initiated important new kinds of research regarding how animals orient and navigate. Orientation is simply facing in the right direction; navigation involves finding one’s way from point A to point B. Early in his research, Kramer found that caged migratory birds became very restless at about the time they would normally have begun migration in the wild. Furthermore, he noticed that as they fluttered around in the cage, they often launched themselves in the direction of their normal migratory route. He then set up experiments with caged starlings and found that their orientation was, in fact, in the proper migratory direction except when the sky was overcast, at which times there was no clear direction to their restless movements. Kramer surmised, therefore, that they were orienting according to the position of the Sun. To test this idea, he blocked their view of the Sun and used mirrors to change its apparent position. He found that under these circumstances, the birds oriented with respect to the new “Sun.” They seemed to be using the Sun as a compass to determine direction. At the time, this idea seemed preposterous. How could a bird navigate by the Sun when some of us lose our way with road maps? Obviously, more testing was in order. So, in another set of experiments, Kramer put identical food boxes around the cage, with food in only one of the boxes.  The boxes were stationary, and the one containing food was always at the same point of the compass.  However, its position with respect to the surroundings could be changed by revolving either the inner cage containing the birds or the outer walls, which served as the background.  As long as the birds could see the Sun, no matter how their surroundings were altered, they went directly to the correct food box.  Whether the box appeared in front of the right wall or the left wall, they showed no signs of confusion. On overcast days, however, the birds were disoriented and had trouble locating their food box. In experimenting with artificial suns, Kramer made another interesting discovery. If the artificial Sun remained stationary, the birds would shift their direction with respect to it at a rate of about 15 degrees per hour, the Sun’s rate of movement across the sky. Apparently, the birds were assuming that the “Sun” they saw was moving at that rate. When the real Sun was visible, however, the birds maintained a constant direction as it moved across the sky. In other words, they were able to compensate for the Sun’s movement. This meant that some sort of biological clock was operating–and a very precise clock at that. What about birds that migrate at night? Perhaps they navigate by the night sky. To test the idea, caged night-migrating birds were placed on the floor of a planetarium during their migratory period. A planetarium is essentially a theater with a domelike ceiling onto which a night sky can be projected for any night of the year. When the planetarium sky matched the sky outside, the birds fluttered in the direction of their normal migration. But when the dome was rotated, the birds changed their direction to match the artificial sky. The results clearly indicated that the birds were orienting according to the stars. There is accumulating evidence indicating that birds navigate by using a wide variety of environmental cues. Other areas under investigation include magnetism, landmarks, coastlines, sonar, and even smells. The studies are complicated by the fact that the data are sometimes contradictory and the mechanisms apparently change from time to time. Furthermore, one sensory ability may back up another.