21. The NBA is _____ organization of professional（职业的） basketball players in the USA.
A. a B. an C. the D. /
22. The Jews _____ a series of disasters in World War II, because the German Nazis wanted to kill all of them.
A. went over B. went after C. went for D. went through
23. Ever since he caught the N1H1, Peter _____ so much pain that he is coughing day and night.
A. suffered from B. has suffered from
C. suffers from D. were suffering from
