On Children's Day 2004,Hong Kong held an interesting activity.In this activity,children and their parents played the rich and the poor.In the dinner,the rich could have delicious food,but the poor could only have bread with porridge. Parents all hoped to have the dinner for the poor with their children.They hoped that their children could be taught a lesson from the dinner. Now many people on earth don't have enough food or clothing.Every day only half of the world could enjoy enough food. The activity was held to make the families understand the differences between the poor and the rich and also make parents know that too much material life won't always do good to the children. From the news report we're clear that  _  .
children often change their minds children of the poor work harder at school children of the rich don't like the activity children shouldn't be given too much material life