国际上对以下哪些能见度定义是正确的?()
A.烟雾的能见度定义为不足1km
B.薄雾的能见度为1km~3km
C.霾的能见度为3km~5km
参考答案:A
Children under sixteen are not permitted to participate in such kind of activities _____ bad for their
mental development. [ ]
A. as is
B. as are
C. that are
D. that they are
生产力的发展、私有制的产生,是警察产生的( )条件。
A.经济条件
B.阶级条件
C.社会条件
D.政治条件