used to 描述过去的习惯 — 英语选择题
题目
Lily 正在整理旧相册，回忆童年。根据语境和语法规则，下列句子中 used to 使用完全正确的一项是：
A. She used to living in a small town when she was a child.
B. She didn't use to like singing, but now she enjoys it a lot.
C. She used to be afraid of the dark, doesn't she?
D. Did she used to play with dolls when she was young?