Assertion: modern surfboard | /r/MadeOf | polyurethane
Facets:
Source sentences:
text: Modern surfboards are made of polyurethane or polystyrene foam covered with layers of fiberglass cloth, and polyester or epoxy resin.
text: Modern surfboards are made of polyurethane or polystyrene foam covered with layers of fiberglass, cloth and polyester or epoxy resin.