【正确答案】 C

【答案解析】本句的意思是：要不是你帮忙，我们永远不能解决这些困难。主句的谓语用的是“would+have+过去分词”，因此选项C．Had it not been是答案，相当于If it had not been.又如：Had it not been for the storm，we should lave retired earlier．要不是这场暴雨我们还会到得早一些。(=If it had not been for the storm，we should have arrived earlier．)If it were not通常用于表示现在及将来情况的虚拟条件句。例如：If it were not for their support，we would be in a very difficult position．要不是有他们的支持，我们的处境会很困难。