21．________ to pass the 2010 college entrance examination made our whole family unhappy.
A．My son failed B．My son's failing
C．My son failing D．My son having failed
22．When I was twenty, I had to drop out before graduation and work in a clothes shop to help ________ my family.
A．supply B．support
C．suppose D．stop
23．It is said that Chen Shuibian is ________ to flee from Taiwan because of the campaign against him.
A．possible B．perhaps
C．probable D．likely
