— Bill, can I get you anything to drink?
— Thanks.
A:You are welcome.
B:It doesn't matter.
C:No problem.
D:I wouldn't mind a coffee.
将一个小球放在竖直放置的弹簧上,用手向下压小球,松手后,小球在弹簧弹力作用下向上运动,请画出此时弹簧对小球的弹力示意图;