A:劳动力短缺
B:兵源不足
C:人口老龄化严重
D:就业困难
关于声现象,下列说法中正确的是( )
已知全集U={1,2,3,4,5,6},集合P={1,3,5},Q={1,2,4},则(∁UP)∪Q=( )
— Mr. Wu. _______ is a good teacher, and often makes _______ lessons interesting.