问题补充：
The Greens used to live in London and now they in Beijing.
A. used to live
B. are used to live
C. are used to living
D. are used for living
答案：
A. used to live
B. are used to live
(答案→)C. are used to living
D. are used for living
解析：句意：格林一家人过去居住在伦敦，现在他们习惯居住在北京。分析：used to do sth.过去常常做某事；be used to doing sth.习惯于做某事。前句表示过去做的事，后句表示习惯做的事，故选C
