1. Better irrigation can dramatically improve crop yield and about 40% of the world's food supply is currently derived from irrigated land. 更好的灌溉可以显著提高作物产量；目前，全球约40%的粮食供应都来自于灌溉地。
2. Finally, the growing population was probably fed by increasing the number and size of irrigated fields. 最后，持续增加的人口很可能是通过不断扩大灌溉土地的面积和规模而得到食物供应的。
3. They irrigated their crops with water from this river. 他们用这条小河里的水浇庄稼。
4. Only 4% of the continent's farmland is irrigated. 整个非洲大陆上只有4%的土地得到灌溉。
5. Only 17% of all the world's agricultural land is irrigated. 全世界农耕地只有17%得到灌溉。
