—I regret you that Mary was badly injured in the accident.
—I can hardly believe my eyes. She is always so careful.
A. informing
B. having informed
C. to inform
D. to have informed
网友回答
A. informing
B. having informed
(答案→)C. to inform
D. to have informed
解析：考查regret用法。动词regret有两个短语：regret to do sth遗憾要做某事；regret doing/having done sth遗憾做了某事；句意：我很遗憾地告诉你Mary在事故中受了重伤。故C心中却。