14.6 as, though 引导的倒装句
 
  as / though引导的让步从句必须将表语或状语提前 (形容词, 副词, 分词, 实义动词提前)。

注意:
    1) 句首名词不能带任何冠词。
    2) 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.

注意:
  让步状语从句中,有though,although时,后面的主句不能有but,但是 though 和yet可连用。