a stubborn problem的用法和样例：
- Dimensional phase unwrapping is a stubborn problem in the image formation of interferometric SAR.
- I had a stubborn cold and coughed day and night.
- There is no reasoning with such a stubborn man as Peter.
- I have a stubborn cold and cough day and night.
- You might as well talk to a stone as try to argue with a stubborn woman.