— Why not turn to your history teacher for help? — .A. I’m too busyB. I’m sorryC. That’s a

问题补充：

— Why not turn to your history teacher for help?

— .

A. I’m too busy

B. I’m sorry

C. That’s a good idea

D. It doesn’t matter

答案：

A. I’m too busy

B. I’m sorry

(答案→)C. That’s a good idea

D. It doesn’t matter

解析：考查交际用语。A我太忙了；B对不起；C这是一个好主意；D没关系；句意：—为什么不向你的历史老师求助？—好主意。根据句意说明C正确。