1．deteriorate /dɪˈtɪəriəreɪt/ v.恶化

英译：to become worse than before

例句：His health has severely deteriorated. 他的健康状况严重恶化了。

2．deposit /dɪˈpɒzɪt/ v.沉淀,沉积

to leave a layer of a substance on thesurface of something, especially gradually

Sand was gradually deposited as the riverslowed down. 随着河水流速变缓,泥沙渐渐沉积下来。

3．degradation /ˌdegrəˈdeɪʃn/ n.退化,恶化

英译：the process of changing to a worse condition

例句：An overuse of natural resources has added to environmentaldegradation. 对自然资源的过度利用加剧了环境的恶化。

4．decay /dɪˈkeɪ/ v.腐烂

英译：to be destroyed gradually by a natural cause

例句：The apple started to decay after being exposed to sunshine for a fewdays. 被阳光照晒了几天之后,这个苹果开始腐烂了。

5．decompose /ˌdiːkəmˈpəʊz/ v.腐烂,分解

英译：to decay or to break down into smaller parts

例句：The fallen leaves gradually decomposed and became part of the soil. 落叶逐渐腐烂分解,成为土壤的一部分。

6．degeneration /dɪˌdʒenəˈreɪʃn/ n.退化,衰减

英译：the process of becoming worse in quality or function

例句：With the increase in age, most people may undergo a degeneration ofhearing and eyesight. 随着年龄的增长,大部分人都会经历听力和视力的退化。

7．deciduous /dɪˈsɪdʒuəs/ adj.(树木)落叶的

英译：(of a tree) losing the leaves in autumn or winter

例句：The oak is deciduous, which loses its leaves at a very late time ofeach year. 橡树属于落叶植物,每年很晚的时候才会落尽树叶。

8．sediment /ˈsedɪmənt/ n.沉淀物

英译：sand or stones lying on the bottom of a river, sea, etc.

The bodies of marine animals will soon becovered by sediment on the bottom of the sea. 海洋动物的尸体很快就会被海底的沉淀物覆盖。

9．wreckage /ˈrekɪdʒ/ n.残骸

英译：the remaining parts of something after it has been badly damaged ordestroyed

例句：The soldiers managed to save all the survivors from the planewreckage. 士兵们成功地将所有幸存者从飞机残骸中救了出来。

10．remnant /ˈremnənt/ n.残余,遗迹

英译：a small part of something left with most of its main part destroyed

例句：These remnants of fossils have helped scientists to study the lifeof dinosaurs. 这些化石遗迹帮助科学家研究恐龙的生活习性。

11．renewable /rɪˈnjuːəbl/ adj.可再生的,再生性的

英译：being able to be replaced naturally without being used up

例句：Researchers have been focusing on developing renewable energyresources. 研究人员一直在致力于开发可再生能源。

12．geographical /ˌdʒiːəˈɡræfɪkl/ adj.地理(学)的

英译：relating to the study of geography

例句：The dust storms have affected a very large geographical area. 沙尘暴已经影响到了很大一片地域。

13．purify /ˈpjʊərɪfaɪ/ v.净化,使纯净

英译：to make something clean or pure

例句：Forests tend to have a huge capacity for purifying air. 森林通常具有强大的空气净化能力。

14. hazard /ˈhæzəd/ n.危险,威胁

英译：something that can be dangerous or cause damage

例句：Growing air pollution has constituted a severe health hazard to thelocals. 空气污染的不断加剧给当地居民的健康造成了严重威胁。

15. toxic /ˈtɒksɪk/ adj.有毒的

英译：poisonous

例句：The volcano is emitting a large amount of toxic gas and smoke. 火山正喷发出大量有毒的气体和烟雾。

16. excessively /ɪkˈsesɪvli/ adv.过分地,极度地

英译：too much or extremely

例句：The excessively high cost of living in some large cities has furtherwidened the wealth gap. 一些大城市过高的生活成本进一步拉开了贫富差距。

17．rainforest /ˈreɪnfɒrɪst/ n.热带雨林

英译：a tropical forest where it rains a lot throughout the year

例句：The Amazon rainforest constitutes a highly complex biologicalsystem. 亚马孙热带雨林构成了一个极其复杂的生态系统。

18. rainfall /ˈreɪnfɔːl/ n.降雨量

英译：the total amount of rain that falls in a particular area over acertain period

例句：The average annual rainfall in Britain is significantly larger thanthat in Egypt. 英国的年平均降雨量远大于埃及的年平均降雨量。