问题补充：
I regret you that the tickets .
A. telling, have sold out
B. to tell, has sold out
C. to tell, have been sold out
D. telling, have been sold out
答案：
A. telling, have sold out
B. to tell, has sold out
(答案→)C. to tell, have been sold out
D. telling, have been sold out
解析：句意：很遗憾的告诉你，票已经卖完了。Regret一般接不定式做宾语，表示具体的动作。结合语境可知下文宾语从句中描述的是现在已经完成的动作，故用选择完成时态在，主语是动作对象，故用被动语态，选C。
