Common mistakes
The middle radical is و or ي. It stretches into a long vowel: قَالَ: and shortens before a consonant ending and in the jussive: قُلْتُ, لَمْ يَقُلْ.
أَجْوَبَ → أَجَابَ Past: heأَجْوَبَتْ → أَجَابَتْ Past: sheأَجْوَبْتَ → أَجَبْتَ Past: you (m.)أَجْوَبْتُ → أَجَبْتُ Past: I