Common mistakes
The second and third radicals are the same letter. They merge: رَدَّ: and come apart again before a consonant ending: رَدَدْتُ.
فَرَرَ → فَرَّ Past: heفَرَرَتْ → فَرَّتْ Past: sheفَرَرُوا → فَرُّوا Past: they (m.)يَفْرِرُ → يَفِرُّ Present: he