Wastewater from factories polluted the river为什么用polluted

问题描述:

Wastewater from factories polluted the river为什么用polluted

pollute 是这个句子的谓语动词,“污染”的意思.而这个污染已经发生了,所以用了过去时polluted.
翻译:来自工厂的废水污染了河水.