阅读下面短文，从短文后各题所给的四个选项A、B、C、D 中，选出可以填入空白处的最佳选项。
When Jane and Billy were little, they were good with each other. But when they were both 10 years old, they started to 1.
"Mom, Billy won't give my book back!"
"It's not yours. It's mine!"
And so it went. Our quiet 2 turned into a war zone (战场). But soon we found a 3 to stop it.
We talked to the kids about what would happen (发生) if they fought4. We thought of a list of "punishments" (惩罚) that we would give them if they fought. 5they weren't really punishments. We just asked them to do some 6things for each other. For example, if Jane started a fight, we would ask 7to clean Billy's room. If Billy started a fight, we would ask him to give his sister a hug (拥抱).
We 8 these "punishments" on a circular board with an arrow (带箭头的圆板) in the middle. If one of them started a fight, he or she would have to turn around the arrow and 9 the "punishment".
This "punishment wheel" worked out well. Soon, the kids 10fighting so often.
We didn't have to really punish them-we just had to teach them to be nice to each other.
