Hvis is a condition, it means: in case. (Please notice that whose also translates into a word spelled hvis.) The sequense of subject s, centraladverb a and verb v in a hvis clause is sav, since a hvis clause is a subordinate clause - the condition element of a main clause.

Hvis du (s) ikke (a) laver (v) øvelser, lærer (v) du (s) ikke (a) dansk

Du (s) lærer (v) ikke (a) dansk, hvis du (s) ikke (a) laver (v) øvelser

Drag and drop to form a sentence - inverted if hvis comes first or straight forward if hvis comes after the main clause.