A string of codes for exchanging items in software or games. Advanced English 1 is a set of English comprehensive ability training materials introduced and adapted by China Central Radio and TV University. The new version of College Advanced English 1 has no activation code, which is a series of codes for exchanging items in software or games. Generally, on the back of the book, there is a three-word activation code written on it, and then the silver thing is scraped open, and there is a string of letters and numbers, which is the activation code.