Believe it or not,the water we flush down our toliets _____ as fresh water!

问题描述:

Believe it or not,the water we flush down our toliets _____ as fresh water!
A.start B.stsrts C.starting D.has started

B.不管你信不信,我们用来冲厕所的水原本是干净的!
we flush down our toilets在句中是做the water的定语从句,主题句就是the water starts as fresh water.