Used to do sth
used to do sth 表示“过去常常做某事”，现在已经不再做了
I used to cook, but I don't have time to cook now.
我以前总做饭，但是现在没时间做了
Tom used to be a couch potato, but he works out everyday now.
Tom以前特别宅，但现在每天都健身
Be used to (doing) sth
Be/get used to (doing) sth 表示“习惯于(做)某事”, 现在依旧在做
He's used to staying up late.
他已经习惯熬夜到很晚了
I've already got used to being a vegetarian.
我已经开始习惯作素食主义者了
be used to do sth
be used to do是“被动语态”，表示“被用于做某事”
It can be used to do the same thing.
这个可以用来做相同的事情
Beer is used to be the party drink.
啤酒可以被用作派对饮品