问题
选择题
________ is known to us all is that the 2016 Olympic Games will take place in Rio de Janeiro.
A．It
B．What
C． As
D．Which
答案
答案：B
题目分析：考查名词性从句。本题考查what引导的主语从句，从句中缺少主语，故用关系词what引导。句意：众所周知，2016年奥运会将在里约热内卢举办。故B正确。