im not exactly sure what your asking but im assuming your asking to find the singular plural if so then the answers are
(1) el chico
(2) la chica
(3) una cosa
(4) la profesora
(5) un libro
(6) la amiga
(7) el senor
(8) una leccion
(9) la pasajera
(10)un conductor
(11)el estudiante
(12)la turista
(13)el joven
(14)un problema
Hope i helped in any way , i wish you the best of luck ... take care
( Im sincerely sorry if this isnt what your asking for )
