Klingt Deutsch! is an application which helps you to learn German irregular verbs, articles and prepositions.
The method is World-old, yet simple and working!
– You start learning by heart, repeating question cards in the loop.
– Select how many cards per one exercise you would like to loop.
– Set how many times you should answer to mark the card as ‘leart’.
– If the card has a status ‘learnt’, a new card is automatically added.
– Keep answering the cards until they are over.
– Reset statistics to start all over again.
Prepositions exercises were taken from http://german.about.com