【正确答案】 A

【答案解析】 考查虚拟语气。句意：要不是你的帮助，我就不会提前完成这项工作。If条件句可与but for，without，otherwise，or等短语转换，此句可转换为if非真实条件句为“If I hadn't had your help, I wouldn't have finished the work ahead of time”。此句为对过去的虚拟，主句谓语动词用，would/should/could/might+have done，故选A。