used to do 过去常常（表示现在不再）
used to do过去常常,过去曾经；过去常常做某事
He used to do his homework on Sunday,but now he often does homework on Saturday.
他过去在星期天做家庭作业,但是现在他经常在星期六做作业.
eg:I used to swim in the lake near my village when I was young.
be used to doing习惯于做某事
eg:My grandpa is used to going for a walk after dinner.
be used to do 被用于...
eg:Wood can be used to make paper
"I used to do this rather regularly,particularly with shoplifters," the judge said.
“我以前经常这么判决,特别是对那些商店扒手,”法官说.
有一点需要补充.在选择题中看到be used to时,应当首先根据句子判断其所要的意思是什么,然后在决定选哪一个．另外,当习惯做某事时,由于to是介词,所以要加动名词doing；而be used to do sth.是使用的被动语态,所以后面加动词原型．另外,如果强调渐渐适应,还可以用get used to doing sth.
