I’m afraid there might have been 1000 audience in the concert last night, _____?
The professor can answer almost any question __________we have about any history topic.
Due to the light pollution, stars are too faint _________with naked eyes in the urban area.
--Why won’t you go to Jim’s birthday party with us? --Well, I don’t like him, if you ________know.
He failed the driving test though he __________for a long time.
Hotels fill up fast during the busy tourist season, __________it is necessary for tourists to make reservations in advance.