学员疑问： 老师，这句话为什么用“Had I known”开头？原句是“If I had known the truth, I would have acted differently.”

老师解答： 虚拟语气中，若条件句含“had”“were”“should”时，可省略“if”并倒装。原句“If I had known”省略“if”后，需将“had”提前至主语前，变为“Had I known”。此结构更正式，常见于书面语。例如：“Had she studied harder, she would have passed the exam.”（= If she had studied harder...）。

点评分析：要掌握虚拟语气倒装规则。倒装后句子结构需严格遵循“Had/Were/Should + 主语 + 动词原形”的格式，且主句仍需用“would/could/might have done”。此考点在阅读理解长难句和写作中高频出现，需通过典型例句强化语法意识，避免混淆倒装与正常语序。