—Do you think I should accept his invitation Jim?—If I were you．I certainly would．A. None

问题补充：

—Do you think I should accept his invitation，Jim?

—．If I were you．I certainly would．

A. None of your business．

B. It depends．

C. Why not?

D. I don think so．

答案：

A. None of your business．

B. It depends．

(答案→)C. Why not?

D. I don think so．

解析：A不关你的事情；B看情况而定；C为什么不？D我不这么认为。句意：—你认为我应该接受那个邀请吗？—为什么不？如果我是你，我就接受。根据后面的If I were you, I certainly would.说明后者建议他接受。故C正确。