used to do, be used to doing,be

1)used to do：过去常常做某事，但现在不了。

He used to be a teacher.   He didn't use to paly football.

2)be/get used to doing：习惯于做什么，强调的是如今的习惯。

He is used to taking a walk in the morning. He gets used to living in the country now.

3)be used to do：被动语态，被用作

Wood is used to make paper.