Create your own training with an unlimited number of questions and answers or rather front and back flashcards.
Then practice wherever and whenever you want by trying to find what the back of the card is hiding. Check by clicking on it and see if you succeeded or not. The cards you have the most difficulty with will appear more and conversely those you have the easiest will appear less. You can even reverse the order to see the answers first and then the questions.
In the settings of your training you have the possibility to modify, add or remove cards. The green cards are very well known, while the red ones are very poorly known.
Have fun and good luck!

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