___ three times in a row, the boxer decided to make a fourth attempt, though．
A．Having defeated B．To have defeated
C．Having been defeated D．To defeat
___ is well known is that Africa had contacts with India and the Red Sea civilizations from the earliest times．
A．As B．It C．What D．That
The truly homeless are the rich who __ _ their home into a hotel hall．
A．will turn B．turned
C．are turning D．have turned
—George, ___ _ you sing so loudly at such a late hour?
—I am terribly sorry．
A．will B．may C．must D．shall
All the drivers have been warned that driving after drinking shall __ __ serious accidents．
A．bring up B．bring back C．bring in D．bring about
Depression is the leading cause of suicide, __ __ in turn is the third leading cause of death among 15 to 24 year olds in the United States．
A．who B．which C．that D．what
