自重(含驾驶员)
3×104N
每个轮胎触地面积
3×10﹣2m2
车轮个数
10
车厢容积
10m3
提出元素周期律并根据元素周期律编制第一个元素周期表的科学家是( )
——I can hardly believe my eyes. Is that you, Lucy?——Yes. It has been almost 20 years______ we were together.
49-30=____
57-50=____
92-80=____
78-40=____
69-50=____
85-60=____
46-20=____
读图,判断正确的说法是( )