1. The dialogue is between Lin Jun and Li Dashan discussing their classes and homework. Lin Jun asks Li Dashan about whose books they are and what types of books they are.
2. Li Dashan says one book is his English book, while another is his engineering textbook. They discuss that Li Dashan's English class is not difficult but has lots of homework, while his engineering class is difficult but does not have much homework.
3. Lin Jun says he is learning Chinese and their Chinese homework assignments are substantial. Li Dashan asks Lin Jun to clarify what something is and confirms it is his Chinese homework.