–-Do you know about Han Han?Yes he a playful student when he was in secondary school

问题补充：

–-Do you know about Han Han?

--Yes, he a playful student when he was in secondary school, but now he is one of the most popular writers in China.

A. was used to be

B. used to be

C. was used to being

D. was used for

答案：

A. was used to be

(答案→)B. used to be

C. was used to being

D. was used for

解析：本题的含义是韩寒在上中学的时候，是一个顽皮的学生，表示过去的事，可用used to+动词原形表示以前或曾今的意思，符合本题题意，故本题选B。