### Chinese: 小时候，幸福是一件东西，拥有就幸福； 长大后，幸福是一个目标，达到就幸福； 成熟后发现，幸福原来是一种心态，领悟就幸福。
### English: When you are a child, happiness is a thing, and it's a matter of having it; when you grow up, happiness is a goal, and when you achieve it, you will be happy; when you're mature, you discover that happiness is a state of mind, and the realization is a matter of happiness.
### Errors: There is a minor error at "of having". There is a major error at "the realization is". There is a major error at "matter of happiness".

### Improved English: When we were children, happiness was a thing, and we were happy when we had it; when we grow up, happiness is a goal, and we will be happy when we reach it; after maturity, I found that happiness is actually a state of mind, and understanding is happiness.