题目详情

  The problem of pollution is also of great social concern. Continued population increase, accompanied by a rise in the level of living standards, not only threatens to exhaust American resources but pollutes the environment to such an extent that production in the thickly settled area is impossible without damaging the health of the local residents.

  Smog, once an urban annoyance, is now recognized as a health risk, and the automobile has been pinpointed as the principal culprit. Heavy industries have been blamed for river, soil, air, noise and visual pollutions. DDT and other chemical remedies have been doing more ecological harm than the good that they may have brought along.

  Several decades ago, Americans dumped raw sewage into rivers and many industrial plants are now still dumping chemical pollutants into lakes, rivers and oceans. Oceans used to be and are still being considered to be a reserve of seafood. Today, after the oceans have become the home of all pollutants, this use of the oceans is being reduced at an alarming rate.

  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.

正确答案及解析

正确答案
解析

污染问题也受到了社会的极大关注。生活水平在提高,人口在持续增长,这不仅预示着美国资源面临枯竭,而且污染环境到了极严重的地步:人口密集区的工业生产与当地居民的健康已成为不可调和的矛盾。

  烟雾,原先不过是居民的一件烦恼事,现在被公认为危害健康的大敌。汽车已被指控为损害健康的罪魁祸首。重工业因污染河流、土壤、空气、产生噪音和妨碍人们的视觉而备受指责。DDT及其他化学药剂对生态的影响是弊大于利。

  几十年前,美国人把未经处理的污水倒入河流,而许多工厂如今仍在把化学污染物倒入湖泊、江河和海洋。人们一向认为海洋是海产品的宝库。今天,海洋已成为一切污染物的集中地之后,海产品正以惊人速度缩减。

  大城市及其周边是污染最严重的地方。在那里,人为污染物的扩散超过了空气和水将污染物分解稀释到安全水平的能力。自然界生态循环依赖于植物;植物吸收一些污染物,把氧气释放到空气中。但邻近大城市的地区,天然植被日见稀少,而移植的树木、观赏灌木及花园又远不足以吸收机动车辆和工业带来的空气污染物。最后,有些污染物,尤其是臭名昭彰的原子能废料,可能会继续污染空气、土地和水达几千年之久。因此,生态危机——也称为生态灾难或生态灭绝——一段时期以来不仅是生态活动家和环保主义者关注的主要问题,而且引起了其他领域许多科学家和许多国家的政府当局的重视。

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