a rags-to-riches story的用法和样例：
- It was a rags to riches story at a hospital in northern Italy when an 80-year-old homeless man was found to be carrying 10,000 euros and another 20,000 euros worth of lire.
- Hers was a classic tale of rags to riches.
- There is not a rag to cover him.
- The story is about a young girl from the country who went from rags to riches.
- He went from rags to riches in only three years.