Wouldn't it be useful in your flashcards to have some contextual information (which you already do to a limited extent with M,F,N gender)? For example, in Level 2 Session 14 German, the English is "Up/Upstairs" and I answered "nach oben"....but the program's answer was "oben". Two cards later the prompt was "Down/Downstairs", so I answered "unten"....and the answer given was "nach unten"! I realize that both can be used, and understand that without motion, "nach" isn't present, but I still think having some context would be useful (e.g., when giving prepositional phrases with a preposition such as "in" that can take either dative or accusative, depending on context). Just my 2¢ (€0.022)!