The worst pollution threat is concentrated in and near large cities. There the people-made pollutants increasingly surpass the ability of air and water to dilute (冲淡;稀释) the contaminants (污染物) to safe levels. The natural ecological cycle depends on plants, which absorb some pollutants and release oxygen to the air. But near large cities, natural vegetation becomes scarce, and introduced trees, ornamental shrubs and gardens are far from adequate in absorbing motor vehicle and industrial air pollutants. Finally, some pollutants, most notably atomic waste, may continue to contaminate air, land, and water for thousands of years. Therefore, ecocrisis—ecocatastrophe or ecocide—has been for some time one of the major concerns of not only the ecoactivists and environmentalists, but of many scientists of other fields and the government authorities of many countries as well.
The worst pollution threat is concentrated in and near large cities. There the people-made pollutants increasingly surpass the ability of air and water to dilute (冲淡;稀释) the contaminants (污染物) to safe levels. The natural ecological cycle depends on plants, which absorb some pollutants and release oxygen to the air. But near large cities, natural vegetation becomes scarce, and introduced trees, ornamental shrubs and gardens are far from adequate in absorbing motor vehicle and industrial air pollutants. Finally, some pollutants, most notably atomic waste, may continue to contaminate air, land, and water for thousands of years. Therefore, ecocrisis—ecocatastrophe or ecocide—has been for some time one of the major concerns of not only the ecoactivists and environmentalists, but of many scientists of other fields and the government authorities of many countries as well.
One of the worst things that can happen when you are in the _______ for composing is a total lack of ideas.
The city suffered the worst US air _____ since l979.
The author's attitude toward "the 'worst' list" (line 8) is best described as ______.
One of the worst things that can happen when you are in the _______ for composing is a total lack of ideas.
According to the article, what is the worst problem facing people living in cities?
The city suffered the worst US air _____ since l979.
The worst atmospheric condition for dispersion of H2S is().
One of the worst things that can happen when you are in the _______ for composing is a total lack of ideas.