GRE阅读写作分析--A water warning_GRE写作

GRE阅读写作分析--A water warning

　　Let me quickly illustrate some of the links between food and water. It takes about one litre of water to produce one calorie from food crops. The actual water requirements differ according to plant, climate and the efficiency of irrigation.

　　这样做有两点好处：

　　1、看到最后会发现通过离我们最近的food来入手解释这个问题浅显易懂，容易引起读着兴趣。

　　2、其实也是一种变相对比：连最基本的food方面水资源都供应不及了，还要花那么多用在biofeul上，进而从另一个方面支持作者的观点：必须减少在biofeul上的投入

　　这种引入式地分析问题显得很有思维深度，值得借鉴

　　Diets are another variable. Europeans and Americans have for years had high proportions of meat in their diets, but now this trend is catching on in emerging markets as incomes rise. Meat requires ten times the water withdrawn per calorie by plants. So the average daily diet in California requires some 6,000 litres of water in agriculture, compared with 3,000 litres in countries such as Tunisia and Egypt.

Compare these 3,000-6,000 daily litres withdrawn per head of world population for farming the food we eat with the three to four litres we drink or the 300-600 litres of water needed for other purposes, such as hygiene, or manufacturing .

　　Water withdrawals for agriculture continue to increase rapidly. In some of the most fertile regions of the world overuse of water, mainly for agriculture, is leading to sinking water tables. Groundwater is being withdrawn, no longer as a buffer over the year, but in a structural way, mainly because water is seen as a free good.