tpo47 reading2

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

Ants and the other social members of their order, certain bees and wasps, have complete metarnorphosis in four life stages; egg, larva, pupa, and adult.

要看好插入语，对比

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.

有什么选什么不全没关系

就是说别的条件可能改变

But how is this well-insulated nest ventilated（to let fresh air into a room）? Its many occupants（someone who lives in a house） 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（to enclose or fortify with a fence or a ridge of earth）? 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.

Even the pores in the wall are filled with water, which almost stops the diffusion of gases. If not through the walls or its pores, how does oxygen enter the nest at all, since the nest has a closed surface?

然后说如果没有pore, 怎么办

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, Macroternes 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.