To maintain a stable score of 140 in junior high school English, you should focus on the following aspects:

1. Consistent practice: Regularly take English tests and practice questions to maintain your test-taking skills and familiarity with the format.

3. Study habits: Develop good study habits, such as regularly reviewing vocabulary, grammar rules, and reading comprehension strategies.

4. Broaden your knowledge: Read English books, articles, and stories to improve your language skills and gain a deeper understanding of different topics.

By following these tips, you can maintain a stable score of 140 in junior high school English.