Slunce vyšlo nad horu (kam?) a stojí nad horou (kde?) The sun rose above the mountain and stands above the mountain.
Schoval se pod stůl, (kam?); jest schován pod stolem. (kde?) He hid under the table; he is hidden under the table.
Vyšel jsem před dům (kam?), stojím před domem. (kde?) I stepped before the house. I am standing before the house.
NOTE! Před týdnem. A week ago. (Týden zpátky is an anglicism.)
Na, on, v, in, is followed by the objective when it denotes a direction of motion in answer to kam? Where to?; and is followed by the locative when it denotes a location in answer to kde? Where at?
Dej knihu na stůl (kam?) Kniha jest na stole (kde?) Lay the book on the table. The book lies on the table.
V, connects only rarely with the ob. Ex. Upadl v nemoc. He became sick.
Za, behind, followed by the accusative in answer to kam? Where to? (direction), and is followed by the instrumental in answer to kde? Where at? Position. Schovej se za stůl (kam?) Hide behind the table. Sedíme za stolem. We sit behind the table.
Za, during, expressing time is followed by the possessive (genitive). Za krásného dne. During a beautiful day.