问题补充:
He used to his teaching when he was young.
A. devote to
B. be devoted to
C. devoting to
D. being devoted to
答案:
A. devote to
(答案→)B. be devoted to
C. devoting to
D. being devoted to
解析:used to 接动词原形表示”过去常常”;”致力于”应该是devote one-selt to 或be devoted to…,所以答案为B。