497　used to do sth.的用法

　used to do sth. 表示“过去常常做某事”，只表示过去，不可指现在或将来；否定式为didn't use to do sth.，也可用used not to do sth.或usedn't to do sth.，读作[′ju?snt]；一般疑问句，可以把used放在句首，或用助动词did，反意疑问句的附加问句用did或used。

She used to see him last year. 她去年常见到他。

He used not to live in this city. 他过去不住在这个城市里。

He didn't use to be so thin. 他过去不这么瘦。

There used to be a green field there; now there's a supermarket. 过去那儿是一片绿色的田野，现在是超级市场。

Did you use to play the piano? 你过去弹钢琴吗？

Used you to know her? 你过去认识她吗？

There used to be a tree here, didn't there? 这里从前有一棵树，是吗？

You used to swim in summer, usedn't you? 从前你夏天游泳，不是吗？

There used to be a church to the south of the village. 村庄的南面从前有一个教堂。

There used to be few people who were willing to do this sort of job. 过去很少有人愿意干这一行。