Only after class _____ to raise the question.

Only after class _____ to raise the question.
A、did he allowed
B、was he allowed
C、he was allowed
D、did he allow
【正确答案】：B
【题目解析】：本题考查倒装。only在句首引起的句子，通常要使用倒装语序。如果不放在句首，则不必使用倒装语序。根据句意，这句话应该用被动语态，即he was allowed to…。因此倒装时be 动词提前。