问题
选择题
_____excites us greatly that the torch relay of 2008 Olympics will be held in QuFu, the hometown of Confucius.
A．What
B．That
C．It
D．As
答案
答案：C
it 作形式主语,代替后面真正的主语 that引导的从句。其他三无此功能。若把that改为逗号,答案为D, 是as 引导的非限制性定语从句; 若在that前加上is, 答案为A, 是what 引导的主语从句。