Adding a prefix onto a simple verb may have one of the following three results:
1. a Perfective verb with the same meaning: the Perfective partner of the simple verb.
  писђть 'write' написђть 'write'
2. a Perfective verb with a different meaning.
  вестќ 'lead' перевестќ 'translate'
3. a Perfective verb with the same meaning, except that something is said about the time or manner in which the action is carried out. This is the action-type Perfective.
  ходќть 'come/go' сходќть 'make a quick trip somewhere and back'
The only way to tell which meaning a prefix will have is to look it up in a dictionary. A given prefix may have any one of the above three functions, depending on the verb it is tacked onto, e.g.
1. дљлать сдљлать 'do, make' (Perfective partner — no change in meaning.)
2. писђть списђть 'copy' (Change in meaning.)
3. ходќть сходќть 'make a quick trip' (Action-type Perfective.)