I prefer to download e-books online and read them on my mobile phone. Basically, I watch it for about an hour before going to bed every day. This is a habit of mine. Buying books is really expensive. I seldom buy it now. Unless you can't find it online. For example, manuals for human use, currency wars, Tibetan classics, things from the Ming Dynasty, and so on. What I've been watching recently is downloaded from the internet to my mobile phone. Convenient to carry around, you can watch it if you want. It costs nothing. Like ordinary mobile phones, they all support JAVA software. You can read the next JAR book by installing it on your mobile phone.