It’s time for the meeting,but no one has come .What’s the matter?I'm really sorry!I____you the meeting was put off.Aforgot telling Bshould have toldChad had
It’s time for the meeting,but no one has come .What’s the matter?
I'm really sorry!I____you the meeting was put off.
Aforgot telling Bshould have told
Chad had
A
B should have told是虚拟语气，虽然意义上是应该告诉而没告诉，但是语气毫无客气，再看前面的I'm really sorry，就知道不该选这个。
C had had是过去完成时，我已经告诉你会议延后了，和前面的矛盾了
B
B should have told
forget telling A因为FORGET后+ING
B should have told 本应该的意思
应该是A！
晕,中学生的题,B
B
should have done是指本来应该做而事实上没有做的,我本应该告诉你会议推迟了,但我事实上没有告诉你.
forget+doing表示忘记做过某事,放在上句中表示我忘记已经告诉过你会议推迟了,也就是说我告诉过你会议推迟了,但是我忘记做过了这件事
forget+to do 表示忘记要做某事.我忘记要告诉你会议被推迟了,就是还没告诉你
had had 这里的意思是我在某个时间以前就已经把这件事告诉你了,要有一个已过去的参照时间
肯定选B
意思是：我本来应该告诉你会议已经取消了的。
B表示的就是本来应该做而没做，A是已经做了，但自己忘了已经做了。
而句子中的意思很显然是前者。