We don’t think we’ll be able to go mountain-climbing tomorrowthe weather turns o

问题补充：

--- We don’t think we’ll be able to go mountain-climbing tomorrow.

--- the weather turns out fine?

A. How come

B. How about

C. What if

D. Why not

答案：

A. How come

B. How about

(答案→)C. What if

D. Why not

解析：这是一组对话。上文，我认为我们明天不能去爬山。下文，要是天气变好又怎么样？How come为什么How about怎么样What if要是……又怎么样Why not为什么不，根据题意，故选C。