∵A={3,5,7},CUA={2},
∴U={2,3,5,7},
故答案为:{2,3,5,7}.
语音知识(共5小题,每小题1分,满分5分)
小题1:radiation
A.category
B.persuade
C.lack
D.contrary小题2:style A. ugly B. yellow C identify D. yesterday
小题3:worth
A.breath
B.bathes
C.though
D.southern小题4:example
A.experience
B.exhibition
C.examine
D.exercise小题5:discourage
A.route
B.dangerous
C.wound
D.trouble