as if引导的虚拟句是否遵循时态倒退原则呢?He talks about Rome as if he had been

as if引导的虚拟句是否遵循时态倒退原则呢?He talks about Rome as if he had been there before如何解释

as if 一般来说是遵循倒退原则的.但请具体结合虚拟时态部分来学习.
楼主是不明白为什么用had been吗?那你觉得应该用什么?
如果看不出来我们可以先还原.比如它是一个一般的句子.
He talks about Rome,because he has been there before.
这句应该没问题吧,表示以前去过.那现在的谈话其实是对过去事件的虚拟,相应的就是had been.
这也是高中英语常考的题型：主句和从句时态不一致.要根据说话的时间所指和内容来判断.并不是一个句子只能有一种时态.
as if 句型最重要的是掌握如：he speaks french,as if he were a frenchman.这类的句型.