6+20=____
50+50=____
22-2=____
33-30=____
4、如图所示,甲、乙、丙三个相同的杠杆,所挂的物体受到的重力均为G,它们分别在方向如图所示的力F1、F2、F3作用下处于平衡状态,那么
分析如图并回答:
- Do you know the boy in blue?
- Yes. I ________ him several times since last month.
I often ____ (购物)on the weekend.(根据汉语提示填空)
结合以下图表分析,有关说法正确的是( )