We learned Lesson 6 in Book 4, and after that, we have the level of B2. After learning the second book, you should have the level of A2. The vocabulary of this book is limited, so all the words in this book must be firmly mastered (including preposition collocation, example sentences, etc. ).

There are also A 1, A2, B 1 and so on. They are all formulated in accordance with the framework of European language standards, and the standards of textbooks are basically the same.