A:He watched TV.
B:He studied for an English test.
C:He finished his math test paper.
钩码总重/N
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
弹簧长度/cm
4.5
5.0
5.5
5.8
弹簧伸长量/cm
3.3