【正确答案】 B

【答案解析】[解析] 本题考查的是与过去事实相反的虚拟条件省略结构的用法。表示与过去相反的假设，用的句式为“If+主语+had done，主语+would/should/could/might+ have done”，如：If you had come earlier, you might have met him．如果If省略，从句主谓需倒装，故选项B为正确答案。
[避错指南] A项、C项和D项都不能构成相应的虚拟语气，故均排除。除了本题考查的这类虚拟语气之外，还要注意以下两种虚拟语气的表达方式：与现在事实相反时从句用“动词过去式/were”，主句用“would/should/ could/might+动词原形”；与将来事实相反时从句用“动词过去式/were+ to do”，而主句须用“would/should/could/ might+动词原形”。如：If I saw him tomorrow, I should ask him shout it.