Common mistakes
The second and third radicals are the same letter. They merge: رَدَّ: and come apart again before a consonant ending: رَدَدْتُ.
اِسْتَقْلَلَ → اِسْتَقَلَّ Past: heاِسْتَقْلَلَتْ → اِسْتَقَلَّتْ Past: sheاِسْتَقْلَلُوا → اِسْتَقَلُّوا Past: they (m.)يَسْتَقْلِلُ → يَسْتَقِلُّ Present: he