With hundreds of attractions, Beijing is a city ________ makes a lasting impression on its visitors.
A．which B．where
C．what D．when
Just use this room for the time being, and we'll offer you a larger one ________ it becomes available.
A．as soon as B．unless
C．as far as D．until
Everything was placed exactly ________ it used to be before she left the laboratory.
A．why B．when
C．where D．though
________ I'm mistaken, I've seen that tall man at a party before.
A．If B．As
C．Unless D．When
Beijing is ranked first in terms of traffic jams and expenses for culture ________ Guangzhou is more open to peasant workers than Beijing and Shanghai.
A．when B．since
C．while D．because
________ he stops driving himself like this, he'll have a breakdown.
A．Until B．Once
C．Since D．Unless
