used to do 和 be used to doing

含义

1. I used to do something = I did it regularly in the past but no longer do it. 'I used to…' is past. 过去时。过去做某事，但现在不做了。

2. I'm used to (doing) something = it isn't strange or new for me. 我已习惯某事。

示例

1. I used to live alone.(=I lived alone in the past, not any more)

2. I am used to living alone.(=I live alone, and I don't find it strange or difficult because I've been living alone for some time.)

参考

1. Version: 1.4(2014-10-8). "iOS App - Murphy's English Grammar in Use" Unit 18, Unit 61.