There are ___ days in a week and Tuesday is ____ day of the week .

A．seven ; third

B．seven ; the third

C．seventh ; three

D．the seventh ; three

Not until all the fish in the river died _________ how serious the pollution was.    [ ]

A. did the villagers realize        

B. the villagers realized    

C. the villagers did realize        

D. didn't the villagers realize