Your advice was a great help to us, without which all our efforts .
A.wouldn’t pay off
B.hadn’t paid off
C.wouldn’t have paid off
D.didn’t pay off
网友回答
C解析考查虚拟语气。根据前面的was和句意可知本题是一个由without引导的与过去事实相反含蓄条件句，使用情态动词+have done的形式。句意：你的建议对我们很有益，要是没有你的建议，我们的努力就不会得到回报。