Will you have a free evening tonight? let’s have a dinner together.A. If notB. Why notC.

问题补充：

Will you have a free evening tonight? , let’s have a dinner together.

A. If not

B. Why not

C. If so

D. What’ more

答案：

A. If not

B. Why not

(答案→)C. If so

D. What’ more

解析：考查省略结构。If so如果是这样的话。句意：你今晚有空吗？如果有的话，让我们一起吃饭。