The mother told a story to her child:

The mother gave him two toys when the child was young. The child hold a toy in one hand, and another toy in the other hand. Then the mother gave him a toy; he clipped the toy that was on the hands with his arm quickly, stretched out his hand for the third toy.

When you heard this story, you may be feel that he is quite clever, the mother may also think so. However, when you think carefully, you will find he is very stupid. When he clipped a toy and took two toys, how he to play well? If he discards any one toy, the situation will be greatly improved.

He learned to play the harmonica on this day, melodious sound echoed through the park.

Sometimes, the appropriate discard is to grasp the more meaningful things.