“过去常常”和“习惯于做某事”用“use”怎么说？

be used to 后面可以搭配do, 也可搭配doing

be used to do 被用于做...
be used to doing 习惯于做...

由于在表习惯的时候,to相当于介词,所以后面是现在分词.

过去常常做: used to do (谓语直接用used,没有be)

1. I used to swim in the morning.(我过去常在早上游泳.)
2. It is used to make paper. (它被用于造纸)
3. I am used to swimming in the morning. (我习惯于在早上游泳.)

be used to

be used to do

be use to doing 习惯
be use to do 过去常常

过去常常:use to do,没有be
习惯于做某事:be use to doing

过去常常:be used to doing
习惯于:used to do