The word "mountain" means that vocabulary is like a mountain, many of which are wide and far from the top, while the language sea means that you are knowledgeable and knowledgeable, and your knowledge is as profound as the sea.

As long as it is about words, it can be written according to the given topic. Four-word idioms describing knowledge, such as learned, knowledgeable, brilliant, well-read, knowledgeable, versatile, versatile, and reading thousands of books.