A:and then he bega
B:when he bega
C:to begi
D:than he bega
—Where's Sam?
—He _______ for a test in his room.
清政府与八国联军签订《辛丑条约》的时间是( )
甲数的18和乙数的25%相等,(甲数、乙数≠0)则( )