The red book serial number can be unbound. The little red book is a regular publication, and the publishing company will put the serial number behind the published book when printing and distributing it. After buying the book, check the last page of the book by yourself.

The serial number of the little red book is on the cover of the book. If the cover of the book is impossible, you have bought a pirated book.

The serial number is on the scratch card on the book cover. Scan the little red book app and enter the serial number and password in the audio QR code to download.

Little red book backs the word app. You can choose "know" and "don't know" or recite words according to the options. Both methods can be selected.

If you are familiar with the meaning of this word when reciting it, you can click "Know" and the word will not appear today. If you don't know the meaning of the word or want to know the specific meaning of the word when reviewing, click "Don't know" and you will get a detailed explanation of the meaning of the word.

In fact, you carefully read the "help center" in the little red book vocabulary app and understood everything.