When we sleep, we cover our bodies with a piece of clothing (of certain thickness) which I have always called a blanket. As far as I know, the sheet is used to cover the bed. I was surprised to see in my visual dictionary that both the blanket (first layer) and the sheet (second layer) are used to cover the mattress, and that the comforter is used to cover the body when it is cold. Can you confirm that information? What do you use to cover your bodies when you sleep: a blanket or a comforter?