postards have pictures on them, these pictures are things that may never be seen again. the pictures are a part of our history that shows things. because of this many collectors would pay a lot of money for them.
i read on google they "offer a glimpse into the past"
hope this : )
personally, i think you need to answer this question yourself because if you do end up talking to your parent/teacher, then it wouldn't be exactly like the way i describe how i do it, but anyways:
i can lock eyes with them to make sure they know i'm listening and not disregarding what they say, i could also keep still to be able to hear what they are saying and not be distracted by other things around me.
after i listen to what they say, i'll answer what they are asking based on what i know or what they have asked. if it's something that i have to answer, then either answer right away if you know it, or let them know that you need a second to reply to their question.