Verb aspect formation
- It's almost impossible in Russian to predict how a perfective verb is formed. Most dictionaries will list both forms in the same entry.
Some perfectives are formed by adding a prefix to the imperfective form:
| imperfective | perfective |
| делать | сделать |
| строить | построить |
- Some aspect pairs are formed by extending the stem of the imperfective form with an infix:
| imperfective | perfective |
| показывать | показать |
- If one verb of the pair is conjugation I, and the other is conjugation II, most often the conjugation II verb will be perfective:
| imperfective | perfective |
| кончать | кончить |
| отвечать | ответить |
- Some aspect pairs are formed from two different stems:
| imperfective | perfective |
| говорить | сказать |