A:spends, practicing playing
B:spends, practicing play
C:spend, to practice playing
D:spending, practice playing
火车钻山洞时,车轮在钢轨上滚动的声音跟火车在洞外行驶相比 ( )
化学与科技、社会、生活有着密切的联系,下列有关说法正确的是( )