I thought it might be a good idea to download a vocabularytrainer that asks me the vocabulary i need to study. After writing down every difficult words (i already skipped the easy words). I actually saw how much it in fact is. I only wrote down the first two lessons and have over 70 words to study now. Not to mention that i actually should know the vocabulary of lessons 3 by now, too. It will be hard work i think. Luckily it's only the words you don't need that often and question words that are hard.