Common mistakes
The root ends in و or ي, and the endings themselves change. Three patterns cover it: دَعَا يَدْعُو, رَمَى يَرْمِي and نَسِيَ يَنْسَى.
سَمَّيَ → سَمَّى Past: heسَمَّيَتْ → سَمَّتْ Past: sheسَمَّيُوا → سَمَّوْا Past: they (m.)يُسَمِّيُ → يُسَمِّي Present: he