a castle in Spain的用法和样例：
- Don't trust him any more. He is always living in a castle in Spain as a daydreamer.
- He is building castle in spain among his book.
- What he talk about is just a castle in the air.
- There is no building a castle in the air.
- You have thought is merely a castle in the air.
- Your plan is nearly a castle in the sky.