Dongao's account can be used by two people at the same time. If you restrict the use of two mobile phones and two computers, you can't use the third computer to attend classes online. If more than two users use Dongao's online school account, there will be suspicion of serial number.

There are two main types of activation codes, one is the activation code of general software, and the other is the activation code of games. Some software will add password programs and use activation codes in order to make their software face a specific group of people. Only by entering the correct password can you use this software normally.