[Features of LET'S GO Course Book App] LET'S GO to the English World App is an application developed for use with textbooks. We have all 15 content in the App. The LET'S GO Coursebook App consists of the following contents. 1. Textbook MP3 2. Animation video (Word Chant, Song, Mini Talk, Story) 3. Word Flashcard 4. Activity (Word Quiz, Find the Sentence, Make Sentences) [Features of LET'S GO Course Book Textbook] Total 15 books (1 ~ 5 steps, each A B C book) 1. Elementary English curriculum li