Common mistakes
The second and third radicals are the same letter. They merge: رَدَّ: and come apart again before a consonant ending: رَدَدْتُ.
دَلَلَ → دَلَّ Past: heدَلَلَتْ → دَلَّتْ Past: sheدَلَلُوا → دَلُّوا Past: they (m.)يَدْلُلُ → يَدُلُّ Present: he