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
________ my teacher didn't tell me directly, I still felt that I didn't live up to her expectation.
A．When B．Since
C．As D．While
I was wondering what to do with my car which won't start ________ a kind man offered to help.
A．while B．and
C．so D．when
________ much advice you give him, he does exactly what he wants.
A．No matter B．Whether
C．Whatever D．However
________ you have to do the job, you should try your best to do it well even though it may be very difficult for you.
A．Since B．While
C．Unless D．Though
