sentences: aluminum is a kind of material & aluminum is recyclable ->  aluminum is a kind of material that is recyclable  aluminum is a kind of material that is recyclable & recyclable means a material can be recycled many times ->  aluminum can be recycled many times  aluminum can be recycled many times & aluminum is a nonrenewable resource ->  aluminum is a nonrenewable resource that can be recycled many times  aluminum is a nonrenewable resource that can be recycled many times & recycling nonrenewable resources has a positive impact on the environment ->  recycling aluminum has a positive impact on the environment  recycling aluminum has a positive impact on the environment & recycling is a kind of method of disposal -> recycling aluminum is the best way to dispose aluminum