问题
选择题
When I was at school, I _____ up very late, reading storybooks.
A．used to stay
B．was used to stay
C．used to staying
D．is used to staying
答案
答案：A
题目分析：句意：当我上学的时候，常常熬夜很晚看故事书。Used to do过去常常，be used to do被用来（不符合句意），be used to doing习惯做，应该是was used to doing，所以选A。