I was surprised by what she said, made me recognize what silly mistakes I had made.
A. what
B. that
C. which
D. Who
网友回答
A. what
B. that
(答案→)C. which
D. Who
解析： 句意为：他说的话让我很吃惊，这让我意识到自己犯下了多么愚蠢的错误
主句。从主句和从句的关系看，缺成分，用关系代词that或which或who，在限制性定语从句中不用that，再结合句意得出which，which代替前面的整个情况。
考点: 定语从句关系词的考察