Bad habits, _______ formed, are difficult, and sometimes impossible to shake off.
A．before B．once C．until D．unless
I will never know what was on his mind at the time, nor will _______.
A．anyone B．anyone else
C．everyone D．no one else
A small plane crashed into a hillside five miles east of the city, _______ all four people on board.
A．killed B．to kill C．kills D．killing
—Jenny, it won’t be long before I receive the admission letter from Oxford University.
—_______
A．Good luck! B．Congratulations!
C．Why so soon? D．Don’t worry．
In my opinion, everyone has periods in their lives _______ everything seems very hard.
A．when B．where C．which D．that
Tom _______ the TV set for $500，which was much cheaper than he had expected．
A．bought B．paid C．cost D．spent
