was known to them all that Bob had broken his promise he would give them a rise.

____ was known to them all that Bob had broken his promise ____ he would give them a rise.

　 A. As; which 　 B. What; that     C. It; that 　  D. It; which

试题答案

C

解析:

此处It为形式主语,第一个that引导主语从句,第二个that引导同位语从句。