『新东方在线托福听力』为托福考生准备了ETS托福TPO/Official 55 Passage 3阅读练习，TPO/Official 55 Passage 3原文答案解析，TPO/Official 55 Passage 3阅读原文练习音频翻译。

托福TPO/Official 55 Passage 3阅读原文题目答案及解析-新东方托福官方网校手机版

在开阔的草原上，大型动物无处藏身。

In open grasslands there is no place for a large animal to hide.

因此，一些细微的动作会暴露捕食者的存在，一只警惕的食草动物会因为这些动作在捕食者有足够近的距离发起攻击之前发现它的存在。

Thus a watchful grazing animal will see the slight movement that betrays the presence of a predator long before it is close enough to launch an attack.

这听起来好像猎人(捕食者)根本没有机会。

It sounds as though the hunters (predators) stand no chance at all.

不幸的是，对于食草动物来说，生活并不是那么简单。

Unfortunately for the grazers, life is not so simple, however.

食草动物必须低下头，面朝地面进食。

A grazing animal must lower its head and look at the ground to feed.

它的注意力可能只被占据了几秒钟，然后它就抬起头，继续观察，同时咀嚼嘴里的食物，但猎人是耐心和熟练的并且注意力集中。

Its attention may be occupied for only a few seconds before it raises its head and resumes its watch while chewing the food it took, but hunters are patient and skillful and are concentrating intensely.

这几秒钟的时间足以让猎人向前走几步，然后静止不动，身体紧贴地面。

Those few seconds provide time enough to advance a few steps and then freeze, body flattened against the ground.

这可能需要几个小时，但最终这些重复的小前进会让猎人进入范围之内——近到足以赶超它的猎物——漫长的狩猎时间将是值得的，因为最终的盛宴将非常有营养。

It may take hours, but eventually these repeated small advances will put the hunter within range-close enough to outrun its prey--and the long time the hunt has taken will have been worthwhile, because the resulting feast will be highly nutritious.

显然食草动物处于不利地位，因为它们吃东西的时候很容易受到攻击。

Clearly the grazers are at a disadvantage, because while they eat they are vulnerable to attack.

然而，猎人也有一个弱点，正是这个弱点让食草动物得以生存。

The hunters also have a weakness, however, and it is one that allows the grazers to survive.

Hunters can attack only one prey animal at a time.

这甚至应用于团队狩猎的掠食者，如狮子、狼和猎狗。

This applies even to the predators that hunt as a team, such as lionesses, wolves, and hunting dogs.

团队合作使它们能够猎杀比自己大得多、强壮得多的动物，也能猎杀得更成功，但不允许它们一次攻击一个以上的个体。

Their hunt involves running down or ambushing an individual Teamwork allows them to hunt animals much bigger and stronger than themselves and to hunt more successfully, but it does not allow them to attack more than one individual at a time.

食草动物利用这一弱点，尽可能地让捕食者难以选择一个个体作为目标。

The grazers exploit this weakness by making it as difficult as they can for the predators to choose an individual as a target.

它们并不是分散在草地上单独吃草，而是成群地在一起吃草。

They do not graze alone, scattered widely across the landscape, but together, as a herd.

接近的猎人看到的不是一只单独的动物，而是一群动物，所有的动物都在移动，所以他们经常交叉彼此的路径。

The approaching hunter sees not a solitary animal, but a crowd of animals, all of them moving, so they are constantly crossing and recrossing each other’s paths.

猎人刚选择了一个目标，另一只动物就会从它面前穿过，目标就会消失在兽群中。

No sooner does the hunter choose an individual than another animal has crossed in front of it and the target has disappeared into the herd.

从猎人的角度来看，这是特别令它困惑的行为——事实上，确实如此。

From the hunter’s point of view this is highly confusing behavior--as, indeed, it is meant to be.

食草动物还有另一个优势:一群动物比单独生活的动物要警觉得多。

There is another advantage to the grazers: A herd is much more alert than a solitary animal.

动物在进食时必须放松警惕，但在一个兽群中，随时都有一些动物低下头吃草，而另一些动物则抬起头来观察。

An animal has to relax its guard while it is taking food, but in a herd there are at any time some animals with their heads down, biting, and others, with their heads up, watching.

更重要的是，那些抬起头的动物会看向不同的方向，这样它们就能对周围任何地方的动静保持警惕。

What is more, those with their heads up are looking in different directions so that together they are alert to any movement anywhere on the landscape around them.

猎人不可能在不被察觉的情况下接近兽群。

There is no way for a hunter to approach a herd unobserved.

当兽群成员发现麻烦时。它开始移动。

When a member of the herd spots trouble. It starts to move away.

兽群的其他成员跟着它移动，整个兽群也开始移动。如果麻烦很严重而且离得很近，兽群就会逃跑。

Other members of the herd move with it and the entire herd starts to move. If the trouble is serious and close, the herd will run.

发出警报的个体只是在保护自己，但这样做是在给兽群中其他成员示警。

The individual raising the alarm is simply protecting itself, but in doing so it is warning all of the others.

只要兽群的成员们能一起战斗，结果是非常成功的。

Herding is highly successful, provided members of the herd stay together in a fight bunch.

猎人跟着兽群移动，寻找落单的动物。

The hunter moves with the herd, watching for an individual to wander away from the others.

当这种情况发生时，它会试图在这个个体和兽群之间移动，阻止它重新加入兽群。

When that happens, it tries to move between that individual and the rest of the herd, preventing it from rejoining.

一旦它做到了，猎人就有很大的机会杀死猎物。

Once it has done that the hunter has a good chance of making a kill.

当兽群开始奔跑时，单独的猎人可能会放弃追逐，但一群狼或猎狗会把奔跑的兽群视为一个机会并开始追逐。

If the herd starts to run, a solitary hunter may abandon the chase, but a pack of wolves or hunting dogs will regard the running herd of animals as an opportunity and set off in pursuit.

随着兽群的奔跑，一两只年老的或生病的个体或与母亲分开的幼崽，可能会落在后面。

As the herd runs, one or two old or sick, animals, or young animals that become separated from their mothers, may fall behind.

一旦一个猎人或多个猎人抓住了它们的猎物，它们就对其他食草动物失去了兴趣，因为它们也必须集中精神吃东西，这时兽群就会停止奔跑，那些落在后面的个体就会重新加入到兽群中，它们就会重新开始吃草。

As soon as the hunter or hunters seize their prey, they lose interest in all other grazers since then they, too, must concentrate on eating, at which point the herd stops running, those who were left behind rejoin the group, and they all resume grazing.

According to paragraph 1, which of the following presents a serious difficulty for the predators that hunt animals grazing in grasslands?

Which of the following can be inferred from paragraph 1 about grazing animals?

According to paragraph 2, what is an advantage to predators that hunt as a team?

In paragraph 2, why does the author describe the hunting technique used by predators that hunt as a team?

Which of the following is NOT mentioned in paragraph 4 as a way in which animals that graze as a herd benefit?

The word "provided" in the passage is closest in meaning to

According to paragraph 5, any member of a herd is most at risk from predators when

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.

Look at the four squares  that indicate where the following sentence could be added to the passage. This is because grasslands lack the trees and heavy bush to provide cover for anything but very small animals.  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 worth2 points.

How Herding Can Provide Safety In open grasslands there is no place for a large animal to hide. Thus a watchful grazing animal will see the slight movement that betrays the presence of a predator long before it is close enough to launch an attack. It sounds as though the hunters (predators) stand no chance at all. Unfortunately for the grazers, life is not so simple, however. A grazing animal must lower its head and look at the ground to feed. Its attention may be occupied for only a few seconds before it raises its head and resumes its watch while chewing the food it took, but hunters are patient and skillful and are concentrating intensely. Those few seconds provide time enough to advance a few steps and then freeze, body flattened against the ground. It may take hours, but eventually these repeated small advances will put the hunter within range—close enough to outrun its prey—and the long time the hunt has taken will have been worthwhile, because the resulting feast will be highly nutritious. Clearly the grazers are at a disadvantage, because while they eat they are vulnerable to attack. The hunters also have a weakness, however, and it is one that allows the grazers to survive. Hunters can attack only one prey animal at a time. This applies even to the predators that hunt as a team, such as lionesses, wolves, and hunting dogs. Their hunt involves running down or ambushing an individual. Teamwork allows them to hunt animals much bigger and stronger than themselves and to hunt more successfully, but it does not allow them to attack more than one individual at a time. The grazers exploit this weakness by making it as difficult as they can for the predators to choose an individual as a target. They do not graze alone, scattered widely across the landscape, but together, as a herd. The approaching hunter sees not a solitary animal, but a crowd of animals, all of them moving, so they are constantly crossing and recrossing each other’s paths. No sooner does the hunter choose an individual than another animal has crossed in front of it and the target has disappeared into the herd. There is another advantage to the grazers: A herd is much more alert than a solitary animal. An animal has to relax its guard while it is taking food, but in a herd there are at any time some animals with their heads down, biting, and others, with their heads up, watching. What is more, those with their heads up are looking in different directions so that together they are alert to any movement anywhere on the landscape around them. There is no way for a hunter to approach a herd unobserved. When a member of the herd spots trouble, it starts to move away. Other members of the herd move with it and the entire herd starts to move. If the trouble is serious and close, the herd will run. The individual raising the alarm is simply protecting itself, but in doing so it is warning all of the others. Herding is highly successful, provided members of the herd stay together in a tight bunch. The hunter moves with the herd, watching for an individual to wander away from the others. When that happens, it tries to move between that individual and the rest of the herd, preventing it from rejoining. Once it has done that the hunter has a good chance of making a kill. If the herd starts to run, a solitary hunter may abandon the chase, but a pack of wolves or hunting dogs will regard the running herd of animals as an opportunity and set off in pursuit. As the herd runs, one or two old or sick animals, or young animals that become separated from their mothers, may fall behind. As soon as the hunter or hunters seize their prey, they lose interest in all other grazers since then they, too, must concentrate on eating, at which point the herd stops running, those who were left behind rejoin the group, and they all resume grazing.