The preface on the third page of each textbook of New Horizon says: 1 ~ 4 contains all the core vocabulary of Band 4, and volumes 5 and 6 contain all the vocabulary of Band 6. The new horizons I use are old and all blue. My teacher also said that the vocabulary of CET-6 must be mastered, and the vocabulary in the textbook should not be ignored. I have 5 or 6 volumes of texts, electronic drafts of words and listening comprehension. Contact me if you want.