43[单选题]If you had come here yesterday, you ___ him. A. would see B. could have seen C. saw D. had seen

本题考查虚拟语气中与过去事实相反的假设句结构。解题核心在于：

1. 条件句使用过去完成时（had come），表明假设与过去事实相反；
2. 主句需用"would/could/might + have + 过去分词"的结构；
3. 排除不符合虚拟语气规则的选项。

选项分析

A. would see

• 错误：虚拟语气中，与过去事实相反时，主句动词需用完成时态（have + 过去分词），而would see是简单将来时，不符合要求。

B. could have seen

• 正确：could have seen符合虚拟语气结构，表示"本可以见到"，与条件句的假设关系一致。

C. saw

• 错误：saw是过去式，未体现虚拟语气的完成时态，无法与条件句的假设语境匹配。

D. had seen

• 错误：had seen是过去完成时，通常用于陈述事实，而非虚拟语气的假设情境。