--- I regret you that John has been fired.
--- I can hardly believe my ears. He is such a fine worker.
A. telling
B. having told
C. to tell
D. to have told
网友回答
A. telling
B. having told
(答案→)C. to tell
D. to have told
解析：考查非谓语动词。regret doing 后悔做过某事；regret to do 遗憾地做某事。这里是后者，故选C。