Used to do sth.表示过去经常做某事
Be used to doing sth.表示习惯于做某事或习惯于某事。
例句:I am used to cleaning the room. 我习惯于打扫房间
You are used to playing game. 我习惯玩游戏
ps: be used to doing =get used to doing习惯于做某事
例句:I used to go to school .
I usde to eat junk food.
used to be 表示过去是什么样的 (但现在不是)
例句:I used to be a bed student
You used to be a good student
used to do sth是指过去常常做但现在不做了。
used to emphasize...估计前面省略了一个be动词,be used to do sth是被用来做某事的意思,这样理解整个句子意思更通顺。而单独的used to do sth(前面不加be动词)才是指过去常做某事而现在没有做。