A:用塑料梳子梳干燥的头发,越梳越蓬松
B:通信卫星采用硅光电池板提供电能
C:运送石油的大卡车常在地上拖一条铁链
D:晚上脱化纤毛衣时会有火花产生
将1、2号瓶放回取水处,24h 后取出,测1、2号瓶的溶氧量记作b、c.下列表述不正确的是( )
要使代数式6-2x3的值是负数,则x的取值范围是( )
Basketball is a very popular game in China . Some people like playing it . ZhangLei and LiQiang are very good at playing basketball . Tomorrow they are not going to have lessons . They would like to watch a basketball game . This kind of football is popular around the world .
中央电视台播出的大型电视纪录片《大国崛起》解说词写道:17 世纪,英国“在历史性的转变中抢了先机,已经率先到达了现代文明的入口处……在下两个世纪里,它将傲视全球。”英国“抢占了先机”和“傲视全球”的史实表现分别是( )
如图,在四棱锥P﹣ABCD中,PA⊥底面ABCD,底面ABCD是梯形,其中AD∥BC,BA⊥AD,AC与BD交于点O,M是AB边上的点,已知PA=AD=4,AB=3,BC=2.求证:BC⊥PM.