问题补充：
Our school be an old shoe factory, now we studying here. It is a good place to study.
A. used to , used to
B. is used to , are used to
C. is used to, used to
Dused to, are used to
答案：
A. used to , used to
B. is used to , are used to
C. is used to, used to
(答案→)D. used to, are used to
解析：句意：我们学校曾是一座旧鞋厂，现在我们习惯在这里学习。这是一个好的学习地方。短语used to do过去常常做某事；used to be 过去曾是……; be used to doing sth.习惯做某事；结合语境故选D。
