It may be due to the difficulty of shooting, but also because books and movies are completely different things. Some things in books are difficult to express in movies.

I think relatively speaking, foreign screenwriters should read the original work before adapting it, while domestic screenwriters always write scripts after reading a brief introduction.

Let me talk about a few books and film adaptations that I have read:

"Bright Sword"

The original work mainly talks about what happened after the end of the Anti-Japanese War. There are many The Cultural Revolution was written in great length, while the TV series moved the entire timeline forward, from the beginning of the Anti-Japanese War to the end of the Anti-Japanese War.

This is probably politically sensitive.

"Zhaojun Leaving the Fortress"

I think this TV series is more interesting than the original work. In the original book, after Zhaojun went to Huhanye Chanyu of the Xiongnu, there was a large part of the scene where he interacted with bears. It would have been very difficult to shoot this in the TV series, and the budget would have increased a lot. The TV series mainly tells the story of how Zhaojun gained respect by convincing people with his virtue after going to the Huns.

"Harry Potter and the Philosopher's Stone"

Harry Potter and the Philosopher's Stone. In fact, there are some things in this book that are not suitable for adaptation into a movie. When Rowling wrote it, there was no I never thought about making a movie, such as the wizarding chess scene at the end, but then I saw that it was handled well in the movie. The adaptation of this film has always been handled by Rowling, because the book has not been finished yet, and no one except Rowling knows the ending. Some small details may be very important, so the overall adaptation of Harry Potter still relies on the original work.