一个箱子有64个杯子，现在拿出18个杯子，再装入9个杯子，总共有____个杯子。
The instructions on the bottle are really _______. I can't understand them at all.
说理：____．
拉力F/N
0
0.5
1
1.5
2
2.5
3
3.5
4
弹簧长度/cm
22
23
24
25
26
27
28
28.5
28.6
根据实验数据，你认为：
已知数据:2,-1,3,5,6,5,则这组数据的极差是____
请回答下列问题：
