I can think of many cases, students obviously knew a lot of English words and expressions but couldn’t write a good essay.
A. which
B. as
C. what
D. where
网友回答
A. which
B. as
C. what
(答案→)D. where
解析：考查定语从句。本题定语从句的先行词是many cases，定语从句的句子结构很完整，故使用关系副词的形式。句意：我能够想起很多的情景，在那些情况下，学生很明显地认识很多的单词和短语，但是却写不出好的文章。故D正确。