数一数,下面图中各有几个小正方体?
____个 ____个 ____ 个
两个同学分别沿水平方向拉住弹簧测力计的两端,两个同学各自用了100N的力.请问:弹簧测力计的示数为多少?
The Chinese saying “A tree can't make a forest” tell us that is very important in a football match.