excites us greatly that the torch relay of Olympics will be held in QuFu the hometow

问题补充：

excites us greatly that the torch relay of Olympics will be held in QuFu, the hometown of Confucius.

A. What

B. That

C. It

D. As

答案：

A. What

B. That

(答案→)C. It

D. As

解析：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。