单选题 {{B}}第三篇{{/B}}
{{B}}Spacing in Animals{{/B}}
{{I}}Flight Distance{{/I}}
Any observant person has noticed that a wild animal will allow a man or other potential enemy to approach only up to a given distance before it flees. "Flight distance" is the terms used for this interspecies spacing. As a general rule, there is a positive relationship between the size of an animal and its flight distance — the larger the animal, the greater the distance it must keep between itself and the enemy. An antelope will flee when the enemy is as much as five hundred yards away. The wall lizard's flight distance, on the other hand is about six feet. Flight is the basic means of survival for mobile creatures.
{{/I}}Critical Distance{{/I}}
Critical distance apparently is present wherever and whenever there is a flight reaction. "Critical distance" includes the narrow zone separating flight distance from attack distance. A lion in a zoo will flee from an approaching man until it meets a barrier that it cannot overcome. If the man continues the approach, he soon penetrates the lion's critical distance, at which point the cornered lion reverses direction and begins slowly to stalk the man.
{{I}}Social Distance{{/I}}
Social animals need to stay in touch with each other. Loss of contact with the group can be fatal for a variety of reasons including exposure to enemies. Social distance is not simply the distance at which an animal will lose contact with his group — that is, the distance at which it can no longer see, hear, or smell the group — it is rather a psychological distance, one at which the animal apparently begins to feel anxious when he exceeds its limits. We can think of it as a hidden band that contains the group.
Social distance varies from species to species. It is quite short — apparently only a few yards — among some animals, and quite long among others.
Social distance is not always rigidly fixed but is determined in part by the situation. When the young of apes and humans are mobile but not yet under control of the mother's voice, social distance may be the length of her reach. This is readily observed among the baboons in a zoo. When the baby approaches a certain point, the mother reaches out to seize the end of its tail and pull it back to her. When added control is needed because of danger, social distance shrinks. To show this in man, one has only to watch a family with a number of small children holding hands as they cross a busy street.
单选题 Which of the following is the most appropriate definition of Flight Distance?
【正确答案】 C
【答案解析】此选项最符合原文对flight distance下的定义。
单选题 If an animal's critical distance is penetrated, it will
【正确答案】 A
【答案解析】当动物的关键距离被入侵时,动物将开始进攻。原句为:..., at which point the cornered lion reverses direction and begins slowly to stalk the man. ……这时走投无路的狮子调转头来,开始慢慢地逼近那个人。
单选题 According to the passage, social distance refers to
【正确答案】 B
【答案解析】根据文章相聚距离指心理距离。原句为:..., it is rather a psychological distance.
单选题 Which of the following could best replace the word "band" in "We can think of it as a hidden band that contains the group" (in Paragraph 3)?
【正确答案】 A
【答案解析】从上下文看,band可解释为strip of land(地带)。
单选题 The example of the children holding hands when crossing the street in the last paragraph shows that
【正确答案】 D
【答案解析】最后的这个例子表明相聚距离的存在与否有时由外界因素决定。原句为:Social distance is not always rigidly fixed but is determined in part by the situation.