22.Notuntilallthefishdiedintheriver__________howseriousthepollutionwas.
A.didthevillagersrealizeB.thevillagersrealized
C.thevillagersdidrealizeD.didn’tthevillagersrealize
这题为什么选a?realize不是动词吗?was不也是动词吗?一句话里为什么能有两个动词?