单项选择题

问答题 Directions: For this part, you are allowed 30 minutes to write a short essay entitled Global Shortage of Fresh Water. You should write at least 150 words following the outline given below.1.人们以为淡水是取之不尽的；2.实际上淡水是非常紧缺的并分析其原因；3.我们应该怎么办。