问题描述: they didn't clean the classroom yesterday.the classroom ___ ___ yesterday.改为被动语态! 1个回答 分类:英语 2014-10-27 问题解答: 我来补答 wasn't cleaned.首先根据yesterday确定是过去时态,所以be动词一定是was,加上否定词not,然后把clean改为过去分词就好. 展开全文阅读