used的用法to,be used to do,be used to doing,get used to do哪个是“用来做”，“习惯于”，“过去常常做”等等

used to 是用来做
be used to do 是过去常常做
be used to doing 习惯于

.sth.be used to do 某物被用于做某事
2.sth.be used for doing (介绍)某物的用途
3.sb.be used to doing 某人习惯于做某事
4.sb.used to do 某人过去常常做某事

used to do 过去常常做某事。例：I used to get up at 6 o'clock. 我过去常常六点起床。
be used to do 被用来做某事。例：Wood is used to make table.木头被用来做桌子。另一种相同意思的不同用法是：be used for sth. 例：Wood is used for making table/ table.
be used to doing 习惯于做某事=get used to doing. 例：I am used to the new environment. 我习惯了新环境。

used to是过去常常做，be used to doing和get used to doing是习惯于 一个是状态,另一个是动作be used to do是用来做 表被动的

used to do这个短语是初三第二单元的知识点,同时也要讲解你提到的几个知识点.帮助你分析一下.
used to do,过去常常做某事,意思是现在不做了,主语常是人,当然也可以是能实施动作的动物等.
be used to do是use sth to do sth的被动语态形式.主语常常是物,很少是人.
be used to doing,是习惯于做某事的意思,主语也通常是人,但是也可以是能实施动作的动物等.
get used to do是错误的,应该是get used to doing sth.相当于be used to doing.