question: wood:furniture
choices.label: A B C D
choices.text: fiber:water pipe paper:newspaper cotton:clothes metal:cable
explanation: "wood" is the raw material of "furniture". "wood" is a natural material. "furniture" is not necessarily made of "wood". the "fiber" material used in the "water pipe" is a synthetic fiber, and the "water pipe" is not a natural material. "newspaper" is made of processed "paper", which is not a natural material, and "newspaper" must be made of "paper". "clothes" are processed from "cotton", which is a natural material. "clothes" are not necessarily made from "cotton". the material used in "cables" is processed from "metal", but "cables" must be made of "metal".
relation: wood furniture R2.2