非限制性定语从句中的关系代词which和as用法辨析

请看下面两道题： ① He has won the game,_ _was expected.② He has won the game,_ _was unexpected. A. that B. which C. it D. as 以上两题选项中均含有关系代词which和as，该选哪一个呢？现就以下几个方面来谈一谈它们的区别（本文所谈的which和as是指引导非限制性定语从句中的关系代词which和as）。