The students should _________ when the teachers give the lessons.
A:take notes
B:take out
C:take turns
圆x2+y2-4x+6y=0的圆心坐标是( )
3.5×(9.04-14.4÷3.6)=( )
圆x2+y2﹣2x=0和x2+y2+4y=0的位置关系是( )