A:NaOH+H2SO4=NaSO4+H2O
B:Fe+H2SO4=FeSO4+H2↑
C:2NaOH+CuSO4=Na2SO4+Cu(OH)2↓
D:2H2O 2H2↑+O2↑
到两定点F1(-3,0),F2(3,0)的距离之差的绝对值等于6的点M的轨迹( )
–– Can you tell me ________ to China?
–– Sure. Next week.