as引导的让步状语从句一定要用虚拟语气吗
as用于引导让步状语从句，只能用于倒装句式，并且通常可换成though（但不能是although），其基本结构是“名词、形容词、副词、动词等+as [though]+主语+其他”。这类句子通常用陈述语气。如：
Rich as he is, he is not happy. 尽管他很富有，他并不幸福。
Boy as he was, he behaved like a girl. 他虽是个男孩，但举止却像个女孩。
Much as I like you, I couldn't live with you. 我尽管很喜欢你, 却不能和你在一起生活。
Lose money as I did, I got a lot of experience. 钱虽然丢了，我们却得到了许多经验。
Hard though they tried, they couldn't make her change her mind. 尽管他们做了很大努力，却没法让她改变主意。
但有时从句也用“may [might, would]+动词原形”这样的虚拟语气。如：
Clever as you may be, you cannot do that. 尽管你聪明，你却做不了这件事。
Strange though it may seem, he arrived early. 尽管看来很奇怪，他却到得很早。
Try as she might, she could not persuade her friends to go. 不管她怎样想法，都不能劝说她的朋友们去。