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OFFICIAL47 Look at the four squares [■] that indicate where the following sentence could be added to the passage. Where would the sentence best fit? Click on a square [■] to add the sentence to the passage.

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Termite Ingenuity
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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 stage: 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 Luscher 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 Luscher, 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 “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.

13.Look at the four squares [■] that indicate where the following sentence could be added to the passage. Where would the sentence best fit? Click on a square [■] to add the sentence to the passage.

If not through the walls or its pores, how does oxygen enter the nest at all, since the nest has a closed surface? .

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正确答案:B
题目解析:
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【题目翻译】看四个正方形[■],它们表示下面的句子可以加到文章的哪个地方。这个句子最适合哪儿?。 A:如果氧气没有穿过巢壁或者它的毛孔,那么氧气是如何进入巢穴的?因为巢穴的表面是封闭的。 【判定题型】:根据题目问法,题目要求将句子插入到文中最恰当的空格处,故判断本题为句子插入题。 【待插入句分析】待插入句子意为,如果不是通过墙壁和气孔,氧气如何进入巢穴的呢,因为巢穴表面也是密封的。可以推出这句句子前面的话是在描述墙壁和气孔无法让氧气进入。 【原文分析】但是这个隔热良好的巢怎么通风呢?它的许多乘客每天需要超过250夸脱的氧气(超过1200夸脱的空气)。“这么多的氧气怎么能透过土墩的厚壁扩散呢?”■甚至墙上的毛孔都充满了水,几乎阻止了气体的扩散。■答案在于筑巢。■内部由一个大的中心核心组成,真菌生长在其中,下面是空旷空间的“地窖”,上面是空旷空间的“阁楼”,上面是空旷空间的“阁楼”。在巢的外壁上,有许多连接地窖和阁楼的小隧道。真菌花园里温暖的空气从鸟巢上升到阁楼。空气从阁楼进入山脊中的隧道,然后流回地窖。第二个方块后有“答案”两个字,说明前面会有一个问题。 【选项分析】 从整天看,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推出这句句子后面的话可能给出了答案,也就是The answer lies in the construction of the nest,所以待插入句子只能放在B处。

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