a butterfly pupa的用法和样例：
- A man one day pick up a butterfly pupa.
- A butterfly must not be confused with a moth.
- I think this worm is a larva of a butterfly.
- One person, an enterprise, in order to better ourselves, is often very difficult, very painful things, like a metamorphosis into a butterfly pupae.
- A caterpillar is the larva of a butterfly.
- A caterpillar must pass through the cocoon stage to become a butterfly.