— Did you hear the news this morning?
— Oh, yes, was announced on the radio has caused great excitement among the students．
A. that
B. what
C. as
D. it
网友回答
A. that
(答案→)B. what
C. as
D. it
解析：考查主语从句。What引导主语从句并在句中做主语。句意：收音机里宣布的新闻让学生很兴奋。That在名词性从句中不充当任何成分，没有任何意义，只起引导作用。故B正确。