as / though引导的让步从句必须表语或状语提前(形容词、副词、分词、实义动词提前)。
　  Child as /though he was, he knew what was the right thing to do.
　　= Though he was a small child, he knew what was the right thing to do.
注意： a.　句首名词不能带任何冠词。
　　    b.　句首是实义动词，其他助动词放在主语后。如果实义动词有宾语和状语，随实义动词一起放在主语之前。
　　Try hard as he will, he never seems able to do the work satisfactorily.
　　= Though he tries hard, he never seems…
　　虽然他尽了努力，但他的工作总做的不尽人意。