问题补充：
It is difficult to judge whether what he said.
A. is worth to be praised
B. is worthy being praising
C. is worthy of being praised
D. is worth being praised
答案：
A. is worth to be praised
B. is worthy being praising
(答案→)C. is worthy of being praised
D. is worth being praised
解析：动名词表示反复发生的动作，不定式表示一次性的动作，be worth后的动名词要用主动表被动。与worth相似的worthy却不一样，其后不接动名词而接不定式(若接动名词则其前应有介词of)，且要用被动式表示被动含义。
所以选C。
