___is known to all is that the 2016 Olympic Games will take place in Rio de Janeiro
问题描述：
___is known to all is that the 2016 Olympic Games will take place in Rio de Janeiro
A:It B:What C:which D:That
答
xxxxx is that xxxxx
本句中间是以is that连接的,所以前面属于主语从句,应使用What引导,选B怎么不选A选A的话需要把all后面的is去掉