was known to us all that Johnson had broken his promise he would give each of us a small gift.
A. As；which
B. What；that
C. It；that
D. It；which
网友回答
A. As；which
B. What；that
(答案→)C. It；that
D. It；which
解析：第一空it作形式主语，真正的主语是that Johnson...；第二空that引导的是同位语从句，用以解释promise的内容。