Hindi word "kal" is same for yesterday and tomorow , but we recognize it by the sense of sentence or mode of verb. example- mai kal brazil jaunga. tomorow i will go brazil. here " jaunga" is a verb , now it is in a future mode( will + verb ) , here base verb is "jana". second example- mai kal market gaya/ gaya tha. here base verb is "jana" , but "Jana" is in past mode (v2 mode) " gaya/ gaya tha. so after knowing the verb mode you can guess the meaning of tomorrow and yesterday. hope you understand well now!!