Do you have difficulty ____ English?
It was a serious mistake, ______ caused by carelessness.
Can you __________ your e-dictionary to me, please? –Of course. But you mustn’t __________ it to others.
The man in front of me came to _______a sudden stop ______I almost ran into him.
Who’s the man over there?Is it Mr. Black?——It______be him. He’s much taller.
