Were it not for his help,I would have failed the exam.这句话怎特别样理解,特别是前半句,怎样分析它啊

题目

Were it not for his help,I would have failed the exam.这句话怎特别样理解,特别是前半句,怎样分析它啊

答案

be动词放句首是if从句的变异形式,省略if,真正是if it were not for his help如果没有他的帮助,是虚拟语气,与现实相反,所以用be的过去式
例如：If I were you,I would have kissed her.