Used to do sth的用法 1. used to do sth 表示“过去常常做某事”，现在不做了，强调过去和现在的对比，to 后加动词的原形. 2. Used to do 的否定句形式 主语+usedn’t to do/used not to do/didn’t use to do I used to go to school at six o’clock. 否定句I usedn’t to go to school at six o’clock. I didn’t use to go to school at six o’clock. I used not to go to school at six o’clock. 总结：used to do 的句型中used 可以看成情态动词也可看成实义动词 3 .used to do 的疑问句形式及其回答 （1） used sb to do sth? Tom used to watch TV. Used Tom to watch TV? Yes,he used to. 本文来源：https://www.wddqw.com/doc/ba80f22e01020740be1e650e52ea551810a6c983.html