托福阅读TPO30第1篇:Role of Play in Development
Play is easier to define with examples than withconcepts. In any case, in animals it consists ofleaping, running, climbing, throwing, wrestling, andother movements, either along, with objects, or withother animals. Depending on the species, play may be primarily for social interaction,exercise, or exploration. One of the problems in providing a clear definition of play is that itinvolves the same behaviors that take place in other circumstance—dominance, predation,competition, and real fighting. Thus, whether play occurs or not depends on the intention ofthe animals, and the intentions are not always clear from behaviors alone.
Play appears to be a developmental characteristic of animals with fairly sophisticatednervous systems, mainly birds and mammals. Play has been studied most extensively inprimates and canids (dogs). Exactly why animals play is still a matter debated in the researchliterature, and the reasons may not be the same for every species that plays. Determining thefunctions of play is difficult because the functions may be long-term, with beneficial effects notshowing up until the animal's adulthood.
Play is not without considerable costs to the individual animal. Play is usually very active,involving movement in space and, at times, noisemaking. Therefore, it results in the loss offuel or energy that might better be used for growth or for building up fat stores in a younganimal. Another potential cost of this activity is greater exposure to predators since play isattention-getting behavior. Great activities also increase the risk of injury in slipping or falling.
The benefits of play must outweigh costs, or play would not have evolved, according toDarwin' s theory. Some of the potential benefits relate directly to the healthy development ofthe brain and nervous system. In one research study, two groups of young rats were raisedunder different conditions. One group developed in an "enriched" environment, which allowedthe rats to interact with other rats, play with toys, and receive maze training. The other grouplived in an "impoverished" environment in individual cages in a dimly lit room with littlestimulation. At the end of the experiments, the results showed that the actual weight of thebrains of the impoverished rats was less than that of those raised in the enriched environment(though they were fed the same diets). Other studies have shown that greater stimulation notonly affects the size of the brain but also increase the number of connections between the nervecells. Thus, active play may provide necessary stimulation to the growth of synapticconnections in the brain, especially the cerebellum, which is responsible for motor functioningand movements.
Play also stimulates the development of the muscle tissues themselves and may providethe opportunities to practice those movements needed for survival. Prey species, like youngdeer or goats, for example, typically play by performing sudden flight movements and turns,whereas predator species, such as cats, practice stalking, pouncing, and biting.
Play allows a young animal to explore its environment and practice skill in comparativesafety since the surrounding adults generally do not expect the young to deal with threats orpredators. Play can also provide practice in social behaviors needed for courtship and mating.Learning appropriate social behaviors is especially important for species that live in groups,like young monkeys that needed to learn to control selfishness and aggression and tounderstand the give-and-take involved in social groups. They need to learn how to bedominant and submissive because each monkey might have to play either role in the future.Most of these things are learned in the long developmental periods that primates have, duringwhich they engage in countless play experiences with their peers.
There is a danger, of course, that play may be misinterpreted or not recognized as play byothers, potentially leading to aggression. This is especially true when play consists ofpracticing normal aggressive or predator behaviors. Thus, many species have evolved clearsignals to delineate playfulness. Dogs, for example, will wag their tails, get down their frontlegs, and stick their behinds in the air to indicate "what follows is just for play."
1.According to paragraph 1, why is playdifficult to define?
A.Play must be defined with concepts, not examples.
B.Play behavior often looks like nonplay behavior.
C.Play often occurs in the presence of animals that are not playing.
D.Play occurs independently of an animal's intentions.
2.According to paragraph 2, which of the following presents a particular challenge toresearchers who study play behavior in animals
A.The delay between activities and the benefits the animal derives from them.
B.The difficulty in determining which animal species play and which do not.
C.The fact that for most animals, there is no clear transition from youth to full adulthood.
D.The lack of research on the play behavior of animals other than canids and primates.
3.The word "considerable" in the passage paragraph 3 is closest in the meaning to
4.According to paragraph 3, each of the following is a cost to animals that engage inplay EXCEPT
A.exposure to predators.
B.a buildup of fat stores.
C.a loss of fuel that could be used for growth.
D.risk of injury from slipping or falling.
4.从Therefore开始后面的都是potential cost。三种cost已经用红色字体标出。B选项看似提到了，但是原文是说失去了fat store的机会，而不是因为play而build up了。所以B错。
5.Why does the author include the comment "though they were fed the same diets"?
A.To show why rats living in impoverished environments need less food than those living inenriched environments.
B.To eliminate the possibility that differences in diet were responsibly for observed differencesin brain weight.
C.To emphasize the point that rats were fed only the amount of food needed to keep themalive.
D.To suggest that rats fed the same diet have smaller brains than those fed a varied food.
5.这里提到的试验的结果。前面从in one research of study开始描述这个试验，提到了两个对比组，underdifferent conditions。后面是在说结果，括号里面的内容是对结论的解释说明。A,C,D三个选项一点儿都不沾边。只要高中学过一点数理化就知道这个是控制变量的试验，所以答案选B。
6.Paragraph 4 supports which of the following statements about an animal's brain.
A.The heavier the brain, the richer the environment in which the animal was raised.
B.The younger the animal, the harder it is to develop new connections between nerve cells.
C.The larger the animal, the harder it is to develop new connections between nerve cells.
D.The larger the animal's cerebellum, the larger will be the animal's nerve cells.
6.原文中从other studies 开始有描述了另外的观点。说greater stimulation不仅会影响大脑的大小，也会增加神经细胞间的连接的数量，而这个stimulation是由active play提供的。根据上文，环境越复杂，activeplay就越多，因此stimulation就越多，导致动物的大脑更大，也就更重。所以A选项符合这个观点。BCD都没提到。
7.According to paragraph 5, why might play behavior of prey species be differentfrom those of predator species?
A.Unlike predator species, prey species use play to prevent inappropriate socialbehaviors, such as biting.
B.Some prey species are physically incapable of certain types of predator movements.
C.The survival of each species type is linked to particular sets of muscular movements.
D.Predator species have more opportunities to practice play behaviors than prey species.
7.这道题的关键词在于needed for survival。因为prey species和predator species对于survival的要求不同，所以导致他们play behavior也不同。所以选C。 A，B，D原文都没提到。
8.The word "comparative" in the passage paragraph 6 is closest in meaning to
9.Which of the sentences below best expresses the essential information inthehighlighted sentence in the passage paragraph 6 ? Incorrect choices change themeaning in important ways or leave out essential information.
A.Only monkeys that have learned to control their selfish and aggressive behaviors can beinvolved in social groups.
B.Selfish and aggressive animals like monkeys live in groups in order to practice appropriatesocial behaviors.
C.Monkeys and other social animals need to learn behaviors appropriate for their socialgroups.
D.Some monkeys are naturally too selfish and aggressive to understand the give-and-take ofsocial groups, so they learn such important behaviors while young.
9.这道题中的原句主干是learning social behavior is important，特别是对于群居的动物。然后用了monkey做例证。A选项只提到了monkeys要控制自己才能融入群体，但没提到主干部分。 B选项说自私和攻击性强的动物药学social behavior，这就把其他动物排除在外了，改变了原句的意思。C正确，不仅提到了monkey也说到了其他的social animals(which means species that live in groups)为了融入群体要学social behavior。 D是错误选项，原文并没说猴子太自私以至于不能理解give and take…与原文矛盾，不选。
10.What can be inferred from paragraph 6 about the role of adults in play activities ofthe young?
A.Adults help their young learn to become dominant within the social group.
B.Young animals learn how to play from the adults within their social group.
C.Adults allow the young to engage in play behaviors within a protected, sage environment.
D.The long developmental period of some animals allows adults more time to teach their younghow to deal with the threats of predators.
10.根据young & adult定位到第六段第一句。说成年动物要让年轻的动物在相对安全的环境下玩儿。 因此可以得到答案C正确。A原文没有说让young去学怎么dominant，B原文虽然提到social group 但没提到是从adults身上学习。D原文完全没有相关描写。
11.The word "potentially" in the passage paragraph 7 is closest in meaning to
11.potentially潜在地。A市毫无疑问地; B是可能地;C是不幸地;D是快速地。前半句中有May be，表达了一中可能性，后半句没有转折，应该是接上上半句往下说的。所以意思应该想近。
12.According to paragraph 7, how do some animals ensure that other animalsunderstand that they are just playing?
A.By playing only with animals who are not predator.
B.By avoiding any aspects of the play behavior that are dangerous.
C.By practicing non-aggressive and non-predatory behaviors.
D.By using a set of signals that occurs only in play.
12.这一段前半部分一直在描述说有动物之间会误以为是真的aggression，中间出现了thus证明后面会说解决的方法。这里说解决方法是用clear signals 去表达playfulness。所以答案是D。
13. Look at the four squares [■] that indicate where the following sentence can beadded to the passage. Where would the sentence best fit? With messages such asthose, even dogs that are strangers to each other can be playing within a fewminutes.
There is a danger, of course, that play may be misinterpreted or not recognized as play byothers, potentially leading to aggression. ■【A】This is especially true when play consists ofpracticing normal aggressive or predator behaviors. ■【B】Thus,many species have evolvedclear signals to delineate playfulness. ■【C】Dogs, forexample, will wag their tails, get downtheir front legs, and stick their behinds in the air to indicate "what follows is just for play." ■【D】
13.要插入的句子开头为With message such as those，那么说明前面肯定会描述一些messages，后面又说even dogs，那证明前面应该也提到了狗的行为。所以这里应该插在最后一个空里。
14. Directions: an introductory sentence for a brief summary of the passage isprovided below. Complete the summary be selecting the THREE answer choices thatexpress the most important ideas in the passage. Some sentences do not belong inthe summary because they express ideas that are not presented in the passage or areminor ideas in the passage. This question is worth 2 points.
Play appears to be a developmental characteristic of animals with fairly sophisticated nervoussystems, mainly birds and mammals.
A.Although play often resembles aggression, flight, or other purposeful activities, researchersdo not degree on the reasons for and functions of play
B.Although many animals develop physically from play, too many young animals becomevictims of their natural predators while playing.
C.Animals such as rats, dogs, deer, goats and monkeys learn how to be both dominant andsubmissive during play activities so that they will fit in better with their adult social groups.
D.The function of play is still debated in the research literature primarily because each animalspecies uses so few of the many available types of play behavior.
E.Energy expenditure and security risks are some of the costs to animals of play behavior, butthe costs are not so great that they outweigh the long-term benefits of play to the species.
F.As experiments and observations have shown, animals that play at some stages of theirdevelopment obtain neurological, muscular, or social benefits from the play behaviors.
14.选项A对应在原文第一段，提到play的行为包括了running，climbing，fighting等等aggression的行为，但是很难确定其function所以A正确。E对应原文第三段，potential cost提到了loss ofenergy，security risks等等，但是第一段也提到说play是long-term beneficial的，第四段开头说好处一定会outweigh其costs。B这个原文没有提到，虽然第三段提到了potential cost，后面也说adults通常会让young在相对安全的情况下play，但并没有说太多太多的小动物变成了victims。不选。C这个原文虽然说他们要学social behavior，但没提到说这类动物要学着去dominant，不选。D选项对应原文第一段，但选项中的原因和原文不符，不选。E对应原文第三段，potential cost提到了loss of energy，security risks等等，但是第一段也提到说play是long-term beneficial的，第四段开头说好处一定会outweigh其costs。F选项对应原文第四，五段。第四段说play会影响大脑发育，神经细胞间连接的数量。第五段说到了有益于muscletissue的发育。后文第六段也提到了social Benefits。