问题描述： 用英语回答：How to keep water clean?Give out one example. 1个回答 分类： 英语 2014-10-23 问题解答： 我来补答 we should not throw rubbish into river , and we are supposed to save every drop of water , what is more , we must stop factories from pouring waste water into the river ! 展开全文阅读