21. – How about _____ Christmas evening party?
-- I should say it was _________ success.
A. a, a B. the, a C. a, / D. the, /
22. The children do not know how to _______ themselves decently（得体地） at the party.
A. act B. perform C. behave D. advance
23. –Where did you ______ our chemistry teacher?
--It was in the supermarket ______ I bought moon cakes.
A. come to, where B. come across, that
C. come across, where D. come to, that
