Do you still remember هُوَ ?
It means “He”.
When we want to say “He sits”
We add harf يَـ at the start of the verb to represent هُوَ.
sat- جَلَسَ (past tense)
He sits = يَجْلِسُ
*May also present it as هُوَ يَجْلِسُ
A general idea to write فعل مضارع:
Add prefix(يَــ) at the start of the verb for هُوَ.
Last harf: The vowel(baris) dhommah (ُ )
There is a formula to recognise the vowels(baris fathah-dhommah-kasrah).
1. فَعَلَ - يَفْعُلُ
2. فَعَلَ - يَفْعِلُ
3. فَعَلَ - يَفْعَلُ
4. فَعِلَ - يَفْعَلُ
5. فَعُلَ - يَفْعُلُ
6. فَعِلَ - يَفْعِلُ
كَ تَ بَ
فَ عَ لَ
يَ كْ تُ بُ
يَ فْ عُ لُ
The formula is only supported through exposure; reading/hearing.
You will then know which formula is used for which verbs etc.
Do not worry!
You will learn and grasp this along the way!
This is just an introduction on how the vowels are determined and so you will not be confused by the change in vowels.