To me it is missing in most lessons in grammar. Most lessons I learn so that I have the grammar angucke me a time and then I learn only the vocabulary. A little more demanding then it could already be. Otherwise it is very well built, the images and the overall design is very nice. And although the book is in English, it explains some things easier to understand than one or the other book in German. All in all, there are 3 stars, simply because the book challenged me when it comes to grammar.
