[单项选择]As concerns over man’s impact on the global environment increase, many interesting innovations are being considered. For example, "green roofs" - plant-filled roof top gardens - are one substantial way to confront the country’s ecological problems, and there seems to be very little in the way of a downside. For one thing, a green roof acts as a sponge for rainwater, absorbing the majority of water from a typical rainstorm. Only three to five inches of soil for a green roof is sufficient for this to occur, which keeps the weight of the roof to a minimum. Because the plantings on the roof absorb the rainwater, drainage and sewage systems have a decreased volume of water pumping through them, keeping these systems from becoming over-stressed. And while, the soil and plants are absorbing rainwater, they are also taking in pollutants for their own nourishment by storing carbon and then emitting necessary oxygen back into the atmosphere.
The author’s main point in the passage is that
A. green roofs are expensive to install and maintain
B. green roofs are both innovative and eco-friendly
C. global warming concerns have led to many new inventions
D. plant-filled roof gardens emit oxygen into the atmosphere
E. green roofs are the definitive cure for global warming

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[单项选择]As concerns over man’s impact on the global environment increase, many interesting innovations are being considered. For example, "green roofs" - plant-filled roof top gardens - are one substantial way to confront the country’s ecological problems, and there seems to be very little in the way of a downside. For one thing, a green roof acts as a sponge for rainwater, absorbing the majority of water from a typical rainstorm. Only three to five inches of soil for a green roof is sufficient for this to occur, which keeps the weight of the roof to a minimum. Because the plantings on the roof absorb the rainwater, drainage and sewage systems have a decreased volume of water pumping through them, keeping these systems from becoming over-stressed. And while, the soil and plants are absorbing rainwater, they are also taking in pollutants for their own nourishment by storing carbon and then emitting necessary oxygen back into the atmosphere.
The second and third sentences are characterized, r
A. warning and justification
B. generalization and specification
C. invocation and definition
D. authority and reverence
E. confession and resolution

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[单项选择]

A Roof over Our Heads

Man has three basic needs: food, clothing, and shelter. If a man lives in a warm climate, clothing is not absolutely necessary. However, man cannot live without food, and, he has little chance of survival without shelter. Mankind needs shelter to protect him from the weather, wild animals, insects, and his enemies.
Long before man learned how to build houses, he looked for natural shelters, as the animals did. He found that he could protect himself by climbing up into trees or by crouching under the over-hanging edges of cliffs, or by crawling into caves. The first shelters or homes actually built by man were very simple. For his building materials, he used what he could find easily around him: rocks, tree branches, dried grasses, animal skins. It was a long time, however, before man began to build permanent shelters because, until man learned to farm, he lived by hunting. And, in order to follow game, he ha
A. War.
B. Earthquake.
C. Flood.
D. Great fire.

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