sentences: building materials are used to build buildings & a house is a kind of building ->  building materials can be used to build houses  building materials can be used to build houses & wood boards can be used to build houses ->  wood boards are a kind of building material  wood is a renewable resource & a renewable resource is a kind of natural resource ->  wood is a kind of renewable natural resource  wood is a kind of renewable natural resource & wood boards are made of wood ->  wood boards are made of a renewable natural resource  wood boards are a kind of building material & wood boards are made of a renewable natural resource -> wood boards are a kind of building material that is made of a renewable natural resource