structural:reformatting, quality:corruption, linguistic:paraphrasing, information:highlighting, information:classification
A sofa bed or sofa-bed is a multifunctional furniture typically consisting of a sofa or couch that, underneath its seating cushions, hides a metal frame and thin mattress that can be unfolded or opened up to make a bed. A western-style futon differs from a sofa bed, although sofa beds using futon mattresses are common.