It is the test system, _____ the teachers, that is to blame for the heavy burden of middle school students nowadays.
It is a slow process to _______ a good knowledge of English.
All of us burst into laughter _____ we saw Mr. Bean’s funny appearance.
The boy is seriously injured. So he is supposed _________ to hospital as soon as possible.
So difficult did he find _______ to pass the driving test that he decided to give up.
I’m sorry that what I said just now has hurt you, but I didn’t do it _____.