Ri-verbs
Icelandic Ri-verbs have the following principal parts:
| First principal part | Second principal part | Third principal part |
|---|---|---|
| Infinitive | First person singular past tense indicative mood | Past participle |
| Að snúa ("to turn") | Ég sneri ("I turned") | Ég hef snúið ("I have turned") |
| Að gróa ("to heal") | Ég greri' ("I healed") | Ég hef gróið ("I have healed") |
| Að núa ("to rub") | Ég neri' ("I rubbed") | Ég hef núið ("I have rubbed") |
| Að róa ("to row") | Ég reri' ("I rowed") | Ég hef róið ("I have rowed") |
It's possible to make the present subjunctive mood (þótt ég snúi, "though I turn") from the first principal part (að snúa, "to turn"). It's also possible to make the past subjunctive mood (þótt ég sneri, "though I turned") from the second principal part (ég sneri, "I turned").
Read more about this topic: Principal Parts, By Language, Icelandic