21．—My name is Katherine．Shall I spell it for you?
—.
A．Not at all B．Nice to meet you
C．Take it easy D．If you don't mind
22．In ___ year 751, the Chinese traveler Du Huan was taken __．_ prisoner by the Arabic army
A．a, the B．/, the C．the, a D．the,/
23．Everyone agrees that the Philippine police ____．for the tragedy that Hong Kong tourists were killed
A．are to blame B．are to be blamed
C．are being blamed D．have blamed
24．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