问题补充：
Dorothy was always speaking highly of her role in the play, , of course, made the others unhappy.
A. who
B. which
C. this
D. what
答案：
A. who
(答案→)B. which
C. this
D. what
解析：考查定语从句。关系代词Which指代前面一句话的内容，引导非限制性定语从句，在定语从句中做主语。CD项不是定语从句的关系词。A项指代的先行词只能是人。句意：Dorothy总是说她在戏剧中的作用非常重要，这一点让其他人很不开心。故B正确。
