资源简介
1、主从复合句（名词性、形容词性、副词性从句）及连接词。例如：
1）Last week our maths teacher set so difficult an examination problem ______ none of us worked out.
A. that B. which C. as D. who
答案是C。本题考查定语从句的关系代词，关系代词在定语从句中作主语或宾语。work out是及物动词，意为“计算出”，其后应接宾语，这里as作关系代词，和such或so连用。如果本句改为…worked it out，则该题应选为A，构成such…that结构，引导结果状语从句。
