1.Not until all the fish died in the river ____ how serious the pollution was.
A.the villagers realize
B.did the villagers realize
C.didn’t the villagers realize
D.the villagers did realize
2.Not only ____ polluted but _____ crowded.
A.was the city; were the streets
B.the city was; were the streets
C.the city was; the streets were
D.was the city; the streets were