Nouns and adjectives in Czech change their endings to express different concepts and different relationships between words. These changes form a system of grammatical cases. It can be somewhat compared to how English uses prepositions to achieve the same.

Kráva is the basic, dicitionary form - it's called the nominative case and it is used for the subject of a verb. Krávu is the accusative case which is mainly used for the object of a verb.

It might sound confusing, but don't worry; you will slowly learn more about different cases in different skills in the tree.

You may wish to consult the tips & notes sections of every skill (unfortunately available for web only) or Wikipedia as well. Or look at this article that I have found just for you: http://mluvtecesky.net/en/grammar/cases

Hope it helps and happy learning! :)

"Kráva" here is in accusative case, so it changes to "krávu".

Sheree, be sure to read th Tips & Notes sections for this lesson and also the previous lesson on Food. Everything is explained there.