Mrs. Black lives on Second Street. New Year is coming. She wants to send  a card to her friend in Toronto, but she doesn't know where the post office is. She asks her neighbor  Linda, " Is there a post office near here? I want to send a card." "The post office is far from here," says Linda, "but you don't need to go to the post office to post the card. There is a _ in front of the supermarket. You can put your card into the mailbox." Mrs Black and Linda are   _  .
friends sisters mother and daughter neighbors