As an English-as-a-foreign-language teacher (university level), I find this very effective methodology. First, the choice of vocabulary units is well made. Second, the technical snowball is The One That works best to remember words / expressions. When your level of English is already good enough, no vocabulary study book will really work on you: all new words Become The so-called Expired passive vocabulary That You'll never be reliable to use, purpose only understand. So the repetition of words Makes remembering the words really easy! Plus, there are lots of nice colloquial words that sound really native if you use them! The book is a gem!
