a self-portrait by Van Gogh的用法和样例：
- This famous painting was thought to be by Van Gogh, but it is in fact a forgery.
- She acquired an original painting by Van Gogh.
- These paintings by Van Gogh are extremely valuable.
- My favorite painting is Starry Night by Van Gogh.
- The painting is very valuable. It was painted by Van Gogh.