We spent this holiday with our uncle. He loved to go on walks to collect stones. One day, he bought us backpacks(背包） and asked us to go to the mountain with him and carry the stones.

    The whole day we walked around. Every now and then he put stones in our bags. To our surprise, he also took some stones out from our bags. But we thought he had just found better ones. When we returned to the house, we were very tired. The backpacks were so heavy that we felt relaxed when we put them down. Yet our uncle's backpack was half empty.

    “Why did you give us so many stones?” we asked.

    “I didn't. You did.” He said. “You didn't know it, but I gave you a test today. I listened to every word you said. Whenever you were complaining (抱怨), I added a stone to your bags. Whenever you talked about something with positive (积极的) thinking, I took out a stone. And now look at your backpacks.”Our backpacks were full of stones.

    “Your negative(消极的) thoughts are like stones. You carry them in your mind just like those stones in a backpack. Once you have more negative thoughts ,your mind will be heavier.”

    With great love, our uncle taught us one of the most important lessons in life.