您的位置: 首页 > 作业答案 > 英语 > Sam has been skating for four hours.改为否定句 Sam has been skating for four hours.改为否定句 分类: 作业答案 • 2021-12-30 13:36:00 问题描述: Sam has been skating for four hours.改为否定句 答 has换成hasn't