1, "How do cows produce milk? It is a book published by China Railway 20 1 1. The content of this book is mainly about the questions that children all over the world are curious about and how parents should answer their children's questions. This book further explores children's curiosity and exploration spirit.

2. "How do cows produce milk? Introduction: This is the main book series of Welber Publishing House in Germany, which really comes from quality education in Germany; This is entirely put forward by the children themselves, and children all over the world are paying attention to it. Strange, but wonderful. This is a book of knowledge, so that parents can avoid embarrassment when facing the problem of children constantly detonating creativity; Each book contains 20 questions and 40 English words that children are most interested in. Giving the most satisfactory answers to the most critical children will further tap children's curiosity and exploration spirit.