used的三种用法:
1、sth.be used to do某物被用于做谋事;
2、sth.be used for doing(介绍)某物的用途;
3、sb.be used to doing某人习惯于做谋事。
used的例句:People used to come and visit him every day(人们过去每天都来拜访他);Borrowing used not to be recommended(过去是不建议借贷的)。