______so much pollution,it"s hard to clean the water of the river now选B为什么?

题目

______so much pollution,it"s hard to clean the water of the river now选B为什么?
______so much pollution,it"s hard to clean the water of the river now
A.Suffering
B.Having suffered
C.Suffered
D.TO suffer
为什么呢?

答案

很明显这是现在完成时,是否用现在完成时取决于句子的意思,根据后面,现在已经很难清理合理的水了,这是一个影响、后果,原因就是已经被污染了,现在完成时用在句子中一般都是强调对下一句产生影响的.