We should the used water clean before it goes back into the sea.
A:keep
B:make
C:become
下列各句加下划线字的解释有误的一项是( )
已知两圆的半径分别为6和2,两圆心的距离为5,那么这两个圆的公共点的个数是 ( )
c(CH3COO﹣)+c(CH3COOH)=____mol/L
c(H+)____c(CH3COO﹣)﹣c(CH3COOH)+2c(OH﹣) (填“>”、“<”或“=”)