To copy the text content in an e-book, you need to use an e-book reader or browser and open the e-book you want to copy. You can then open a text editor or electronic dictionary in your browser and copy the text into it using the copy and paste function. If you are using an e-book reader, you can press the "Control"+"C" key on the keyboard to copy the text to the whiteboard while reading the e-book. You can then use the contents of the text on the whiteboard or paste it into a text editor or electronic dictionary when you need it. Please note that you should ensure that the text content has been saved to your computer for future use before copying and pasted.