Here the middle radical carries a fatḥah: يَفْعَلُ. Read each row across singular, dual, and plural.
Person
Gender
Singular
Dual
Plural
Third person
Masculine
يَفْعَلُ
يَفْعَلَانِ
يَفْعَلُونَ
Third person
Feminine
تَفْعَلُ
تَفْعَلَانِ
يَفْعَلْنَ
Second person
Masculine
تَفْعَلُ
تَفْعَلَانِ
تَفْعَلُونَ
Second person
Feminine
تَفْعَلِينَ
تَفْعَلَانِ
تَفْعَلْنَ
First person
Masculine/Feminine
أَفْعَلُ
—
نَفْعَلُ
The dash in first-person dual is not a missing form: Arabic uses singular أَفْعَلُ and plural نَفْعَلُ here.