If those old people next-door hadn’t mattered so much to me, I wouldn’t have gone to such lengths to find a solution, and none of this would have ever happened. (Para. 6) 如果我对那些邻居老人毫不在意的话,我就不会千方百计地去寻找解决办法,那么这一切也就不会发生。 在这个句子中,if 引导的是一个非真实条件句,表示与过去事实相反的假设。在这种情况下,if 从句要用过去完成时态,而主句则要用 would have done 的形式。例如: If I (1) my teacher’s advice, I (2) the exam. 如果当初我听从了老师的建议,我考试就不会不及格了。