【答案】is known to us all is that the 2008 Olympic Games

题目：
_____ is known to us all is that the 2008 Olympic Games will take place in Beijing.[     ] A. It B. What C. As D. Which

答案

B 考点名称：主语从句 主语从句的概念： 如果一个句子在复合句中充当一个主语，那么这个句子就是主语从句。主语从句通常由从属连词that，whether，if和连接代词what，who，whichwhatever，whoever以及连接副词how，when，where，why等词引导。that在句中无词义，只起连接作用。