29. Does human activity improve or damage the earth?

The environment is usually changed to benefit human life. Cars and roads make transportation fast and easy, factories make products that make our lives more comfortable, public services in cities like water treatment, electricity, and waste disposal make our lives more convenient. All of these advances, however, come with a significant environmental cost. Human activity does significant damage to the Earth.

One of the main effects of human activity on an area is water pollution. Dumping waste materials from human activity into rivers and streams is popular because the waste seems to disappear downstream. The main sources of water pollution are factory waste, oil and gas runoff from highways, and untreated human waste. When this waste dumped into rivers, the water downstream becomes undrinkable and unusable for agriculture, and also kills plant and animal life in the rivers.

Clean air and water is a prerequisite not only for human life, but also for all life on the planet. But air is now being polluted by modern transportation, notably gas-powered automobiles, as well as electrical generators that burn fossil fuels and pour polluting chemical waste into the air. This makes the air much less healthy to breathe. The air-borne pollution also falls back to the earth in the form of acid rain, which destroys plant life and human buildings.

Another serious long-term effect of air pollution is global warming. For the past several decades scientists have noted a disturbing rise in the average temperature of the earth that caused by the rise of greenhouse gases, air pollutants created by burning fossil fuels, in the atmosphere. Scientists believe that if humans continue to increase the amount of greenhouse gases in the atmosphere, the temperature of the earth will continue to rise. Eventually, this could melt the polar ice caps and cause devastating costal flooding all over the world. Major cities like Hong Kong, Shanghai, and Dalian might be totally destroyed.

Therefore, I believe human activity has caused serious problems while it has improved the world in which we live. It is time to realize this hazard and take action to prevent further disaster while making progress.

译文

29. 人类活动是改善还是破坏了地球？

人们通常是改变环境来为生活带来好处。汽车和公路使运输轻松快捷，工厂生产的产品使我们的生活更加舒适，城市里的公共服务如供水、供电、废物处理使我们的生活更方便。可是所有这些进步都伴随着巨大的环境损失。人类活动确实严重地破坏了地球。

人类活动对地区造成的主要影响之一是对水资源的污染。将人类活动中的垃圾排放到河流中之所以十分普遍，是因为这些垃圾看上去到了下游就消失了。水污染的主要来源之一是工厂废物、石油、公路上的汽油和未经处理的人类垃圾。当这些废物倾入水中后，下游的河水就变得无法饮用，也无法用来灌溉，还会杀死河中的动植物。

清洁的空气和水不仅是人类生存的先决条件，也是地球上所有生命存在的先决条件。但是空气现在已经被现代交通所污染，特别是以汽油为动力的汽车。同样，燃烧化石燃料的发电厂也向空气中排放污染性的化学废物。这使空气呼吸起来更加不健康。空气所受的污染也会以酸雨的形式落回到地球上，它会杀死植物并破坏人类建筑。

空气污染带来的另一个长期严重影响就是全球变暖。在过去的几十年里，科学家们注意到地球的平均气温令人不安地升高，这是由空气中不断增加的温室气体导致的，它是燃烧化石燃料而产生的污染物。科学家们相信，如果人们继续增加空气中温室气体的数量，地球的气温将会继续上升。最后，这会融化两极的冰帽并导致全球性的沿海地区破坏性洪灾。像香港、上海、大连等大城市可能会被完全摧毁。

所以我认为人类的活动在改善我们生活的世界的同时也导致了严重的问题。现在是该在发展的同时认识到这种危险并采取行动阻止更大的灾难发生的时候了。

Word List

• transportation ［ˌtrænspə:ˈteiʃən］ n. 运输，运送
• disposal ［diˈspəuzəl］ n. 处理，处置，布置，安排
• downstream ［ˈdaunstri:m］ adj. 下游的
• dump ［dʌmp］ vt. 倾倒（垃圾），倾卸
• fossil ［ˈfa:səl］ adj. 化石的
• notably ［ˈnəutəbli］ adv. 显著地，特别地
• prerequisite ［ˈpri:ˈrekwizit］ n. 先决条件
• greenhouse ［ˈgri:nhaus］ n. 温室，花房
• devastating ［ˈdevəsteitiŋ］ adj. 破坏性的，强有力的
• hazard ［ˈhæzəd］ n. 危险，冒险的事