知识的提升怎么说英语

To improve your knowledge in a particular subject, you can say that you are "increasing your knowledge" or "expanding your understanding" of that subject. You can also say that you are "learning more" about it or "growing your expertise" in it. Here are a few examples:
I'm trying to increase my knowledge of computer programming by taking online courses.
I'm expanding my understanding of economics by reading books and articles on the subject.
I'm learning more about art history by visiting museums and attending lectures.
I'm growing my expertise in psychology by talking to professionals and doing research.
I hope this helps! Let me know if you have any other questions.