Had you come five minutes earlier , you _____ the train to Birmingham , But now you missed it .A. would catchB. would have caughtC. could catchD. should catch

步骤 1：理解句子结构
句子的前半部分使用了虚拟语气，表示与过去事实相反的假设。后半部分则陈述了事实，即你错过了火车。
步骤 2：分析虚拟语气的时态
虚拟语气的主句使用了“would have caught”，表示与过去事实相反的假设。因此，主句的谓语动词应该使用“would have + 过去分词”的形式。
步骤 3：选择正确的选项
根据虚拟语气的时态，选项B “would have caught” 是正确的。