急!!!!!!!!!關於Chem的問題

"Hard" is a material just has very high tensile modulus / tensile strength but may has not so high elongation at fracture i.e. brittle. E.g. Tungsten
"Strong" is a material has high tensile modulus / tensile strength and high elongation at fracture i.e. have some degree of deform before fracture. E.g. Steel