as / though引导让步状语从句时要用倒装吗
as / though引导让步状语从句时，一般须用部分倒装。如：
Old as / though he is, he works like a young man. 尽管他很老了，但他工作起来却像个年轻人。
Hard as / though he was working, he didn’t pass the exam. 虽然他一直在努力学习，但他还是没有通过那次考试。
Try again as / though he will, he can’t succeed. 尽管他还会再试一试，但是它不会成功。
as / though引起的倒装分三种情况：表语、动词原形及状语的倒装。
一般直接将表语提前到句首，若表语是带不定冠词a / an的单数可数名词，倒装后，不定冠词a / an须被省略。如：
Fine as / though he looks, he is ill with some serious diseases.
Child as / though he is, he knows much about the society.
A. 动词前面带有情态动词may, might, will, would, can, could等时，只将行为动词提到句首，而这些情态动词保留在原处。
Swim as / though he can, he can’t swim so far. 尽管他会游泳，但是他游不得那么远。
Run as / though he did, he didn’t run fast enough to catch the bus. 虽然他跑，但是他跑得不够快而没有赶上汽车。
In the classroom as / though he stays, he doesn’t read his texts. 尽管他呆在教室里，但他不读书。
Carefully as / though he worked, he made some mistakes. 尽管他工作很细心，但还是除了一些差错。