问题补充：
—Any information about your son?
—No. If only I those tough words to him.
A. didn say
B. hadn said
C. shouldn have said
D. couldn have said
答案：
A. didn say
(答案→)B. hadn said
C. shouldn have said
D. couldn have said
解析：if only 引起的句子要用虚拟语气。与wish跟从句用虚拟的规则一样。与过去的事实相反，用过去完成时态。
