Not until his father died what his father really meant.
A. do they realize
B. did they realize
C. realized they
D. had they realized
网友回答
A. do they realize
(答案→)B. did they realize
C. realized they
D. had they realized
解析：考查倒装句：直到父亲去世他才意识到父亲真的意味着什么。Not until+从句倒在句首，这句话用部分倒装句，根据句意：两个动作是同时发生，用一般过去式，选B。