It is exactly ______he often fails in the exam ______ makes his parents worried about him.
| A．what; that | B．that; which | C．that; that | D．what; what |
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 |
Not only ______ polluted but ______ crowded.
| A．was the city; were the streets | B．the city was; were the streets |
| C．was the city; the streets were | D．the city was; the streets were |
---Do you know Jim quarreled with his brother?
--- I don’t know, ______.
A . nor don’t I careB nor do I care
C. I don’t care neitherD. I don’t care also
Not until I began to work ______how much time I had wasted.
| A．didn’t I realize | B．did I realize | C．I didn’t realize | D．I realized |
Not until the early years of the 19th century______ what heat is.
| A．man did know | B．man knew | C．didn’t man know | D．did man know |