碗、筷等餐饮具消毒应该做到一洗、二清、三消毒、四（）
A、保藏
B、保洁
C、烘干
D、晾干
参考答案：B
It is difficult to tell exactly ____ the saying began, but it is probable that it was in the theater or movie industry.
A．where
B．when
C．why
D．that
申请发明、实用新型和外观设计专利三者都必须具有的专利性是（）。
A.新颖性
B.创造性
C.显著性
D.美观性
