问题描述： used todo的否定和疑问形式 1个回答 分类：英语 2014-11-12 问题解答： 我来补答 used to do的否定是didn't use to do或者usedn't to do.He usedn't to be a teacher./He didn't use to be a teacher.used todo的疑问形式是将used提前,或者在句首加did.Used he to be a teacher?Did he use to be a teacher? 展开全文阅读
