used to do sth(情态动词)“used to ”后跟f动词原形,否定形式:usedn't to do / didn't use to do ?翻译:过去常常做某事。加油!不明白再问!如果帮到你,请采纳,谢谢!
used to do sth(情态动词)“used to ”后跟f动词原形,否定形式:usedn't to do / didn't use to do. Be sure.