A:x=−π3
B:x=π3
C:x=−π6
D:x=π6
— I know. In November, 2010. So Guangzhou is busy preparing for it.
自来水管的内直径是2厘米,水管内水的流速是每秒8厘米.一位同学去洗手,走时忘记关掉水龙头,5分钟浪费____升水.