问题描述： they are doing their _____(homework) in the classroom 1个回答 分类：英语 2014-11-25 问题解答： 我来补答 they are doing their homework__(homework) in the classroom填原形,homework是一个不可数名词.do one's homework 做家庭作业 这是五年级的题目,homework是所有家庭作业的统称,没有复数形式.OK? 展开全文阅读
