he seems to know everything.
A. Young as he is, yet
B. Young as he is
C. As he is young, but
D. Though he is young, but
网友回答
A. Young as he is, yet
(答案→)B. Young as he is
C. As he is young, but
D. Though he is young, but
解析：考查倒装，as 意为虽然，尽管，要倒装，后不能出现but 或yet，句意：虽然他很年轻，但是他似乎什么都知道。所以选B。