问题补充：
---Sam, you always run slowly every morning. Do you like it?
---Not really, but .
A. I used to it
B. I’m used to it
C. I used to do it
D. I’m used to do it
答案：
A. I used to it
(答案→)B. I’m used to it
C. I used to do it
D. I’m used to do it
解析：句意：萨姆，你总是每天上午慢跑。你喜欢吗？不是真的喜欢，但是我习惯了。be used to do sth,被用来做……，be used to doing sth / sth习惯于做……，used to do sth,过去常常做某事。故选B。
