设集合U={1,2,3,4,5,6},A={1,2,3},B={2,5,6},则A∩(∁UB)等于( )
A:{2}
B:{2,3}
C:{3}
D:{1,3}
某单位有职工750人,其中青年职工350人,中年职工250人,老年职工150人,为了解该单位职工的心理状况,用分层抽样的方法从中抽取样本,若样本中的青年职工为7人,则样本容量为( )
⑴____ A. must B. public C. question D. cup
⑵____ A. danger B. her C. litter D. mother
⑶____ A. stay B. away C .today D. Saturday
⑷____ A. great B bread C. ready D. head
⑸____ A. dear B. bear C. here D. nearby