Not until all the fish died in the river ___ 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 |
The play went along well until the middle of Act 2 ,_____the excitement began .
A soB but C when D which
He is a man with rich experience , from ______much can be learned .
A whom B which C whereD what
There was _____to prevent the accident .
A something could doB anything we could do
C nothing we couldn’t doD nothing we could do
The book ______is not in the library .
A that I need itB I need itC which I need itD I need
In some countries, ______are called “public schools” are not owned by the state .
A that B which C as D what