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白蚁，一种群居昆虫，在某些物种中有200万甚至更多的个体，经常被错误地称为白色蚂蚁。

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.

与蚂蚁不同，白蚁具有逐渐变态的状态，它只有三个生命阶段：卵、若虫和成虫。

Termites, unlike ants, have gradual metamorphosis with only three life stages: egg, nymph, and adult.

蚂蚁和它们的其他社会成员（某些蜜蜂和黄蜂）在四个生命阶段中完全变态：卵、幼虫、蛹和成虫。

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.

群居的蚂蚁，蜜蜂和黄蜂的工兵阶层仅由雌性组成，它们是单个女王的全部女儿，在成熟后不久就交配，此后再也不交配。

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.

白蚁的工蚁和兵蚁由雄性和雌性组成，而蚁后则与雄性配偶永久生活在一起。

The worker and soldier castes of termites consist of both males and females, and the queen lives permanently with a male consort.

由于白蚁体积小，身体柔软，它们很容易脱水，并且必须生活在相对湿度较高的潮湿地方。

Since termites are small and soft-bodied, they easily become desiccated and must live in moist places with a high relative humidity.

当巢穴的相对湿度高于96%，温度也相当高时，它们的表现最好，温带物种的最佳温度约为79华氏度，热带物种的最佳温度约为86华氏度。

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.

地下白蚁是整个美国东部常见的破坏性物种，它们通过在与木头（它们唯一的食物）接触的潮湿土壤中筑巢来达到这些条件。

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.

周围的土壤使巢保持湿润，并趋于将温度保持在或多或少对它们有利的水平。

The surrounding soil keeps the nest moist and tends to keep the temperature at a more or less favorable level.

冬季寒冷时，地下白蚁移至霜冻线以下的洞穴。

When it is cold in winter, subterranean termites move to burrows below the frost line.

一些热带白蚁是更聪明的工程师，他们用内置的“空调”建造巨大的地上巢穴，以保持巢穴的湿润、恒温和充足的氧气。

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.

这些白蚁中建筑结构最先进的是一种非洲白蚁——纳塔尔大白蚁。

Among the most architecturally advanced of these termites is an African species, Macrotermes natalensis.

瑞士著名的昆虫学家马丁·吕切尔表示，这种培菌白蚁的土墩高达16英尺，底部直径为16英尺，水泥墙状土壤中混有16至23英寸厚的白蚁唾液。

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.

土墩厚而密的墙壁使内部微气候与外界大气的湿度和温度变化隔离开来。

The thick and dense wall of the mound insulates the interior microclimate from the variations in humidity and temperature of the outside atmosphere.

土墩外部的几个狭窄且壁较薄的脊从其底部附近几乎一直延伸到顶部。

Several narrow and relatively thin-walled ridges on the outside of the mound extend from near its base almost to its top.

根据吕切尔的说法，中型的白蚁巢大约有200万个体。

According to Lüscher, a medium-sized nest of Macrotermes has a population of about 2 million individuals.

它们在花园中培养真菌作为食物，这些真菌以及白蚁自身的新陈代谢有助于保持巢的内部温暖，并为巢中的空气提供一些水分。

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.

白蚁通过将水从土壤中运走，使巢中的空气饱和，使其相对湿度达到100％左右。

The termites saturate the atmosphere of the nest, bringing it to about 100 percent relative humidity, by carrying water up from the soil.

但是，绝缘良好的巢穴如何通风？

But how is this well-insulated nest ventilated?

巢穴中许多居住者每天需要大于250夸脱的氧气（超过1,200夸脱的空气）。

Its many occupants require over 250 quarts of oxygen (more than 1,200 quarts of air) per day.

这么多的氧气如何通过土墩的厚壁扩散？

How can so much oxygen diffuse through the thick walls of the mound?

甚至墙壁上的孔都充满了水，这几乎阻止了气体的扩散。

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.

内部由一个大型中央核心组成，真菌在其中生长，在其下方是一个空的“地窖”，在其上方是一个空的“阁楼”，并且在巢外壁上的脊处有连接地窖和阁楼的许多小隧道。

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.

真菌花园中的温暖空气通过巢穴上升到阁楼。

The warm air in the fungus gardens rises through the nest up to the attic.

空气从阁楼进入脊中的隧道，然后向下流回地窖。

From the attic, the air passes into the tunnels in the ridges and flows back down to the cellar.

气体（主要是氧气的进入和二氧化碳的排出）易于扩散到脊中或从脊中扩散出来，因为它们的壁很薄并且表面积大，这是由于它们从土墩的墙向外突出了很远的距离。

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.

因此，通过脊向下流入地窖的空气中的氧气相对丰富，并且损失很多二氧化碳。

Thus air that flows down into the cellar through the ridges is relatively rich in oxygen, and has lost much of its carbon dioxide.

当它上升通过真菌生长区域并返回到阁楼时，它为巢穴的居民提供新鲜的氧气。

It supplies the nest’s inhabitants with fresh oxygen as it rises through the fungus-growing area back up to the attic.

The author mentions “white ants” in the beginning of the passage in order to

According to paragraph 1, which of the following is true about termites?

According to paragraph 2, termites need to live in nests with high humidity in order to

The word “ingenious” in the passage is closest in meaning to

According to paragraph 3, the nests of some tropical termite species have the ability to

According to paragraphs 3 and 4, all of the following are true of the nests of Macrotermes natalensis EXCEPT:

According to paragraph 5, what does the thinness of the ridge walls make possible?

Paragraph 5 supports which of the following about the air that flows through the interior of a Macrotermes natalensis mound?

Look at the four squares  that indicate where the following sentence could be added 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?  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 worth 2 points.

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.