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.
دَعَوَ → دَعَا Past: heدَعَوَتْ → دَعَتْ Past: sheدَعَوُوا → دَعَوْا Past: they (m.)يَدْعُوُ → يَدْعُو Present: he