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.
أَضْيَفَ → أَضَافَ Past: heأَضْيَفَتْ → أَضَافَتْ Past: sheأَضْيَفْتَ → أَضَفْتَ Past: you (m.)أَضْيَفْتُ → أَضَفْتُ Past: I