Friends brought their children to the library to express their verbal thanks. A library is an institution that collects, sorts out and collects books and materials for people to read and refer to. As early as 3000 BC, libraries appeared. Library has the functions of preserving human cultural heritage, developing information resources and participating in social education. Friends who bring their children to the library can express their thanks in person or by sending messages, and their words should be sincere. So friends brought their children to the library to express their oral thanks.