Common mistakes
The second and third radicals are the same letter. They merge: رَدَّ: and come apart again before a consonant ending: رَدَدْتُ.
ظَنَنَ → ظَنَّ Past: heظَنَنَتْ → ظَنَّتْ Past: sheظَنَنُوا → ظَنُّوا Past: they (m.)يَظْنُنُ → يَظُنُّ Present: he