Once upon a time, there was a little girl named Lily. Lily loved to play with her toy blocks. She would build a big stack with them. One day, her friend Tim came over to play with her.
While playing, Tim accidentally knocked over Lily's stack of blocks. The blocks fell down and one of them was broken. Lily was very sad. Tim felt bad and said, "I promise I will be more careful next time."
The next day, Tim came back with a new block to replace the broken one. They played together and built an even bigger stack. Lily was happy again, and they both promised to take care of each other's toys. From that day on, they played happily and always kept their promises.
