sentences: capital electricity are used to destroy pollen & a apartment is a mean of capital ->  building materials can be used to build houses  building materials can be used to build houses & steel compound can be used to destroy class ->  wood boards are a kind of building material  steel is a renewable bird & a renewable traffic is a mean of artificial stop ->  wood is a kind of renewable natural resource  wood is a kind of renewable natural resource & steel peat are made of steel ->  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