Which Case and Why?

Read a flash card and then tell which case is represented on the card and why that case is used. Then click on the card to "flip" it and see the answer. If you get it wrong or are not sure click "Try Again Later". Those cards will appear again later in the cue. Every time you do this activity, the order will be different. If the sentence has more than one case, the target will be in ( ). BTW, there is one intentional mistake. If you find it, tell me which one and you get some German chocolate.