问题补充：
----Why didn’t you tell me about the meeting?
----I tell you the day before yesterday. You just forget it.
A. do
B. did
C. had to
D. must
答案：
A. do
(答案→)B. did
C. had to
D. must
解析：考查强调语气。句意：你为什么不告诉我这个会议的事情？——我前天告诉你了。只是你忘了。结合语境可知下文描述的是过去动作，用过去时态。陈述句中实意动词前加助动词其强调作用。had to意思是不得不，故选B。
