Estoy en la caja y pagaré
The ones with la are feminine and the ones with el are masculine. When the noun ends in an “a” it’s obviously feminine and when a noun ends in “el” it’s obviously masculine. It’s hard to tell whether it’s masculine or feminine when theres los and las and when it doesn’t end in an “a” or “e”
Tu because If you put Mi or mis son rojos it says my are red which dosen't really make sense. Since you put tu in front of son (plual) it would be they are red.
