单项选择题
Why not join us in the game?（）
A.OK! I'm coming B.No, you do the same C.Oh, that's all right D.Don't mention it
单项选择题 Why not（）and do some outdoor activities?
单项选择题 Why not（）boating with us in the park?
单项选择题 Why he did it will remain a（）for ever.
