My sister an English teacher in our school. Now she works in America.A. was used to beB.

问题补充：

My sister an English teacher in our school. Now she works in America.

A. was used to be

B. used to

C. used to be

D. used to being

答案：

A. was used to be

B. used to

(答案→)C. used to be

D. used to being

解析：本题的含义是我的妹妹原先是一名英语教师，used to+动词原形，表示曾今或原先的意思，是单词的原形是be，故本题选C。