With the development of modern technology, digital devices(数码设备)have been seen everywhere. People often check what is h_ in the world on the Internet, keep in touch with friends through emails, or even start to read e-books. H_ ,many people still prefer paper books to e-books because they think that brains work b_ when reading paper books.Now, some scientists have come up with some d_ ideas. They believe how brains work is not greatly affected by the w