阅读理解
Long, long ago, there was a man. He lived in a village. One day, he went to a market and did some shopping. He suddenly found two boxes. Both the two boxes were very beautiful and the man loved them. So he bought the two boxes and took them home.
He looked at the boxes. He didn't know how to use the boxes. He thought it over and decided to do something special. He decided to put all of his happiness in the yellow box and all of his sadness in the black box. He thought that it was funny to do that.
A few days later, the yellow box was very heavy, but the black box was still light.
He didn't know why. He decided to open the two boxes and found out the truth. He opened the yellow box and found nothing. Then he opened the black box and saw a hole (洞)at the bottom(底).
