－Mary，could you please post the letter for me while you are out?
－
A. I'd rather you didn't.
B. It's OK with me.
C. What for?
D. By all means.
网友回答
A. I'd rather you didn't.
B. It's OK with me.
C. What for?
(答案→)D. By all means.
解析：D 考查情景交际。肯定回答别人的请求用by all means，表示“当然可以了”。