C

题目分析：考查虚拟语气：Had it not been for your help ="if" it had not been for your help要不是你的帮忙，是if的非真实条件句的变型，主句的时间是today，和现在相反用would do。选C。

考点：

点评：if的非真实条件句可以进行省略倒装，去掉if，提前should，were，had，做题时要注意。