A:when it was 7
B:when she was 7
C:at 7
D:when I was 7
下列与声有关的语句中所表达的物理含义是:
A.今天“锣鼓喧天,震耳欲聋”,说明锣鼓声的____大;
B.宋祖英的歌声“悦耳动听”,说明宋祖英的歌声的____好;
C.小女孩讲话“脆如银铃”,说明她的说话声____高;
某空瓶的质量为200g,盛满水后质量是1.2kg,若用这个瓶盛满某液体,液体和瓶的总质量是13.8kg,求这种液体的密度?
已知函数f(x)=ax3﹣3x2+b(1<a<2)只有两个零点,则实数loga2+logb2的最小值是( )