--How often do you drop your English teacher a line?-. But usually once a week.A. As us

--How often do you drop your English teacher a line?
--- . But usually once a week.
A. As usual
B. It depends
C. Generally speaking
D. Have no idea

A. As usual(答案→)B. It dependsC. Generally speakingD. Have no idea解析：情景交际。A. 想玩常一样 B. 看情况而定 C. 总的来说 D. 不知道。句意：你多久给你的英语老师写一封信？——看情况而定。但是通常每周一次。故选B。

哦，回答的不错