托福閱讀真題Official 47 Passage 2（一）
2024-04-18 10:56:18 來(lái)源：中國(guó)教育在線
托福閱讀真題Official 47 Passage 2（一）
Termite Ingenuity
Termites,social insects which live in colonies that,in some species,contain 2 million individuals or more,are often incorrectly referred to as white ants.But they are certainly not ants.Termites,unlike ants,have gradual metamorphosis with only three life stages:egg,nymph,and adult.Ants and the other social members of their order,certain bees and wasps,have complete metamorphosis in four life stages:egg,larva,pupa,and adult.The worker and soldier castes of social ants,bees,and wasps consist of only females,all daughters of a single queen that mated soon after she matured and thereafter never mated again.The worker and soldier castes of termites consist of both males and females,and the queen lives permanently with a male consort.
Since termites are small and soft-bodied,they easily become desiccated and must live in moist places with a high relative humidity.They do best when the relative humidity in their nest is above 96 percent and the temperature is fairly high,an optimum of about 79°F for temperate zone species and about 86°F for tropical species.Subterranean termites,the destructive species that occurs commonly throughout the eastern United States,attain these conditions by nesting in moist soil that is in contact with wood,their only food.The surrounding soil keeps the nest moist and tends to keep the temperature at a more or less favorable level.When it is cold in winter,subterranean termites move to burrows below the frost line.
Some tropical termites are more ingenious engineers,constructing huge above-ground nests with built-in“air conditioning”that keeps the nest moist,at a constant temperature,and well supplied with oxygen.Among the most architecturally advanced of these termites is an African species,Macrotermes natalensis.Renowned Swiss entomologist Martin Lüscher described the mounds of this fungus-growing species as being as much as 16 feet tall,16 feet in diameter at their base,and with a cement-like wall of soil mixed with termite saliva that is from 16 to 23 inches thick.The thick and dense wall of the mound insulates the interior microclimate from the variations in humidity and temperature of the outside atmosphere.Several narrow and relatively thin-walled ridges on the outside of the mound extend from near its base almost to its top.
According to Lüscher,a medium-sized nest of Macrotermes has a population of about 2 million individuals.The metabolism of so many termites and of the fungus that they grow in their gardens as food helps keep the interior of the nest warm and supplies some moisture to the air in the nest.The termites saturate the atmosphere of the nest,bringing it to about 100 percent relative humidity,by carrying water up from the soil.
But how is this well-insulated nest ventilated.Its many occupants require over 250 quarts of oxygen(more than 1,200 quarts of air)per day.How can so much oxygen diffuse through the thick walls of the mound.Even the pores in the wall are filled with water,which almost stops the diffusion of gases.The answer lies in the construction of the nest.The interior consists of a large central core in which the fungus is grown,below it is a“cellar”of empty space,above it is an“attic”of empty space,and within the ridges on the outer wall of the nest,there are many small tunnels that connect the cellar and the attic.The warm air in the fungus gardens rises through the nest up to the attic.From the attic,the air passes into the tunnels in the ridges and flows back down to the cellar.Gases,mainly oxygen coming in and carbon dioxide going out,easily diffuse into or out of the ridges,since their walls are thin and their surface area is large because they protrude far out from the wall of the mound.Thus air that flows down into the cellar through the ridges is relatively rich in oxygen,and has lost much of its carbon dioxide.It supplies the nest’s inhabitants with fresh oxygen as it rises through the fungus-growing area back up to the attic.
Question 1 of 14
The author mentions“white ants”in the beginning of the passage in order to
A.correct a common misunderstanding about termites
B.introduce the idea that termites only take the form of ants during certain life stages
C.argue that not all white ants are social insects
D.illustrate the large variety of insect species that live in colonies
正確答案：A
題目詳解
題型分類(lèi)：修辭目的題
題干分析：考察句子之間的關(guān)系
選項(xiàng)分析：
開(kāi)頭第一句提到white ants,termites經(jīng)常被錯(cuò)誤地認(rèn)為是“白色的螞蟻”，第二句又說(shuō)But they are certainly not ants，說(shuō)明作者想要表明白蟻并不是人們認(rèn)為的螞蟻，糾正關(guān)于白蟻的錯(cuò)誤認(rèn)知，即A正確。
B選項(xiàng)對(duì)應(yīng)原文第三句：“...only three life stage:egg,nymph,and adult.”，沒(méi)有提到以螞蟻的形式存在，與原文矛盾。
C選項(xiàng)對(duì)應(yīng)第四句：Ants and the other social members...有四個(gè)生命階段，但并不是在說(shuō)not all white ants are social insects，張冠李戴。
D選項(xiàng)說(shuō)明生活在群落中的昆蟲(chóng)物種種類(lèi)繁多，與原文不符。
Question 2 of 14
According to paragraph 1,which of the following is true about termites?
A.They are a kind of ant,but they are unlike most ants in many ways.
B.They form colonies that grow at first and then gradually decline.
C.Their workers are all males,and their soldiers are all females.
D.They go through a life stage called the nymph stage.
正確答案：D
題目詳解
題型分類(lèi)：事實(shí)信息題
原文定位：根據(jù)題干關(guān)鍵詞termites定位，本段講解內(nèi)容全部圍繞白蟻展開(kāi)，因此需要從整段定位。
選項(xiàng)分析：
原文說(shuō)本段第三句Termites,unlike ants,have gradual metamorphosis with only three life stages:egg,nymph,and adult與選項(xiàng)D對(duì)應(yīng)。
A選項(xiàng)，原文第二句說(shuō)的是白蟻不是螞蟻，而不是They are a kind of ant，與原文矛盾。
B選項(xiàng)，原文沒(méi)有提到聚集地的大小變化，無(wú)中生有。
C選項(xiàng)，原文最后一句說(shuō)的是工蟻中both males and females，而不是all males，張冠李戴。
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