______ the advice of his friends, he would not have suffered such a heavy loss in his business.A. If he tookB. If he should takeC. Were he to takeD. Had he taken

步骤 1：识别虚拟语气类型
题目中提到的“he would not have suffered such a heavy loss in his business”表明这是一个与过去事实相反的虚拟语气。这种虚拟语气通常使用过去完成时态来表达。

步骤 2：分析句子结构
在与过去事实相反的虚拟语气中，if从句通常使用过去完成时态，即“if + 主语 + had + 动词过去分词”。主句则使用“would have + 动词过去分词”来表达。

步骤 3：确定正确选项
根据题目，我们需要找到一个与过去事实相反的虚拟语气的正确表达。选项D “Had he taken” 符合这个要求，因为它使用了过去完成时态，表示与过去事实相反的假设。