A:1
B:1x
C:x+1x
D:x-1x
下列事例中,属于运用了重力方向的是( )
若关于x、y的二元一次方程组2x+y=3k-1x+2y=-2的解满足x+y>1,则k的取值范围是____
Every year, we plant many trees on _______ side of the road to make our city more beautiful.