题目内容：

used to do,be used to doing和 be used to do的区别,并举例说明

优质解答

used to do指：过去常常
例：I used to go to school on foot.
be used to doing指：习惯于做某事
例：He used to taking a shower after lunch.
be used to do指：被用于,主语往往是物.
例：This tool is used to open the box.