models ka use kab aur kaha hota hai

It is use to express modality.

modals can could could have could have been may/might may might have may/might have been should should have should have been would would have would have been has/have to had to used to ought to ought to have able to i play football. मैं फुटबॉल खेलता हु। i can play football. मैं फुटबॉल खेल सकता हु। i could not sleep yesterday. कल रात मै सो नही सका।