I don’t like the lecture yesterday. Most of what the speaker said was the subject.A. on B

问题补充：

I don’t like the lecture yesterday. Most of what the speaker said was the subject.

A. on

B. off

C. of

D. around

答案：

A. on

(答案→)B. off

C. of

D. around

解析：考查介词：off the subject走题，句意是：我不喜欢昨天的讲座，演讲者说的大多数话是走题的。选B。