Question

___, he continued his study. A. Late as it was B. As it was late C. Late although it was 为什么选A

Answer 1

Late as it was是倒装句，
相当于Though it was late

as 当尽管用的时候要倒装

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）。但需注意：
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。例如：
Try hard as he will, he never seems able to do the work satisfactorily. 他工作很努力，但总不能让人满意。

Answer 2

as构成倒装句，表示“虽然，尽管”。
例如：Though he is a child,he knows a lot.=Child as he is,he knows a lot.
虽然他是个小孩，但是他知道的东西很多。（a 必须省略）
Though he is young,he can do the work alone.=Young as he is,
he can do the work alone.
虽然他年轻，但是他可以独自做这项工作。