Question

To command (or request) the third person the form لِيَكْتُبْ is of word كَتَبَ is used. كل طالبٍ is in the place of (raf') because it is الفاعل.

Accepted Answer

لِيَكْتُبْ كَلُّ طالبٍ اسمَهُ في هذه الورقةِ (Let every student write his name on this paper)- - -لِيَحْلِسْ كَلُّ طالبةٍ في مكانِها (Let every female student sit in her place)

Text	To command (or request) the third person the form لِيَكْتُبْ is of word كَتَبَ is used.
Back Extra	لِيَكْتُبْ كَلُّ طالبٍ اسمَهُ في هذه الورقةِ (Let every student write his name on this paper) - - - لِيَحْلِسْ كَلُّ طالبةٍ في مكانِها (Let every female student sit in her place)
Personal Notes	كل طالبٍ is in the place of (raf') because it is الفاعل.

لِيَكْتُبْ كَلُّ طالبٍ في Student Command Request Person