问题补充：
---I stay up late. ---Really? I didn’t. But I working in the night.
A. am used to, am used to
B. used to, used to
C. am used to, used to
D. used to, am used to
答案：
A. am used to, am used to
B. used to, used to
C. am used to, used to
(答案→)D. used to, am used to
解析：be used to sth习惯于某事;used to do sth过去常常做某事.句意:我过去常常熬夜到很晚。——真的吗？我不是。但是我习惯了在晚上工作。故选D。
