unit2 Beware the dirty seas课件.pptVIP

Unit TwoBeware the Dirty Seas（当心肮脏的海洋） I. Pre-reading Questions Is the river near your home town clean or dirty? Take the Pearl River (the Zhujiang River) in Guangzhou, for example. You can take a night cruise on the Pearl River. Is it dirty? If so, what makes it dirty? What can be done about it? II. Water pollution 水污染 Water pollution is a major element of 20th-century environmental pollution. It includes the accumulation in oceans, lakes, rivers, and streams of physical, chemical, and biological substances that are either directly harmful to life or that have dangerous or harmful secondary and long-range effects. The principal sources of water pollution are sewage(污水), industrial waste, garbage and refuse(废物), and agricultural fertilizers(农业化肥), pesticides(杀虫剂), and weed killers(除草剂). II. Water pollution The two chief reasons for the contamination(污染) and exacerbation(恶化) of the problem are industrialization(工业化) and urbanization(城镇化). Industrial wastes include dissolved minerals(溶解矿物质), toxic chemicals, and sediments(沉淀物). Modern industrial processes have polluted water with certain metals, such as lead(铅) and mercury(汞), while agricultural practices do so with a variety of pesticides. The Mediterranean Sea 地中海被北面的欧洲大陆，南面的非洲大陆和东面的亚洲大陆包围着，东西共长约4000千米，南北最宽处大约为1800千米，面积（包括马尔马拉〔Marmara〕海，但不包括黑海）约为2,512,000平方公里(970,000平方英里)，是世界最大的陆间海。地中海是世界上最古老的海，历史比大西洋还要古老。 沿岸国家 欧洲国家（从西至东排序）：西班牙、法国、摩纳哥、意大利、马耳他（岛）、斯洛文尼亚、克罗地亚、波斯尼亚和黑塞哥维那、黑山、阿尔巴尼亚、希腊、塞浦路斯（岛）。 亚洲国家（从北至南排序）：土耳其、叙利亚、黎巴嫩、以色列和巴勒斯坦自治政府。 非洲国家（从东至西排序）：埃及、利比亚、突尼斯、阿尔及利亚、摩洛哥。 地中海作为陆间海，风浪较小，加之沿岸海岸线曲折、岛屿众多，拥有许多天然良好的港口，成为沟通三个大陆的交通要道。这样的条件，使地中海从古代开始海上贸易就很繁盛，促进了古代古埃及文明、古希腊文明、罗马帝国等的发展。现在也是世界海上交通的重要地区之一。其沿岸的腓尼基人、克里特人、希腊人，以及后来的葡萄牙人和西班牙人都是航海业发达的民族。著名的航海家如哥伦布、达·伽马、麦哲伦等，都出自地中海沿岸的国家。 About the article The text is about the polluted sea and arouse our great concerns to our living environment. Every year there is a lot of sewage(污水) poured into the seas. The waste of coastal cities(沿海城市), industry and factories’ poisons, e