After ________ seemed a hopeless wait, four coalminers trapped in the mine for 125 hours were finally rescued in Heilongjiang Province.
A．when B．that
C．it D．what
In the office an electrical engineer is looking through the instructions to know ________ the heat system works before the repair work.
A．whether B．why
C．how D．that
Energy, passion and a burning desire are, you see, ________ true learning takes.
A．that B．what
C．how D．which
________ is the most important for him is not his job, but his family.
A．It B．As
C．What D．That
________ she was invited to the ball made her very happy.
A．Whether B．That
C．Because D．What
Mary is a humorous and warmhearted woman and that is ________ she is a most popular person in her community.
A．whether B．because
C．how D．why
