The feeble coupling between neighboring graphene sheets is what enables graphite to be broken so easily into minuscule wafers that make up the mark left on paper when someone writes with a pencil.

• 由于邻近石墨薄膜层间的连结相当微弱，因此当我们用铅笔写字时，石墨很容易碎裂成微小的薄片，形成纸上的线条。