He ____ the maths examination if he had worked hard enough, but he didn’t.A. would passB. has passedC. would have passedD. passed

本题考查虚拟语气的用法，核心在于判断条件句中与事实相反的情况所对应的时态结构。
关键点：

1. 条件句中“if he had worked hard enough”使用过去完成时，表明与过去事实相反的假设；
2. 主句需用“would have + 过去分词”结构表达本可能实现但未实现的结果。

虚拟语气的结构分析

1. 条件句时态：
   • “if he had worked hard enough”为虚拟条件句，用过去完成时表示与过去事实相反。
2. 主句时态：
   • 对应的主句应使用“would have + 过去分词”（即“would have passed”），表示本可以实现但未实现的结果。

选项辨析

• A. would pass：用于与现在或将来事实相反的情况，不符合题意。
• B. has passed：现在完成时，未体现虚拟语气结构。
• C. would have passed：正确，符合“与过去事实相反”的虚拟语气结构。
• D. passed：简单过去时，未体现虚拟语气。