He is known his being on time so we don’t know the reason his being late this time.A. f

问题补充：

He is known his being on time, so we don’t know the reason his being late this time.

A. for; of

B. as; for

C. for; for

D. of; of

答案：

A. for; of

(答案→)B. as; for

C. for; for

D. of; of

解析：考察介词,be known as一……出名，for为了，后面接名词性短语，表示原因。句意：他一直以守时出名，因此我们不知道他这次迟到的原因。故选B。