Поставьте прилагательные в сравнительной либо отличной ступени. 1. Strength of materials

Поставьте прилагательные в сравнительной либо отличной ступени.
1. Strength of materials is (difficult) than chemistry. 2. This metal is (brittle) than iron. 3. The University is one of the (tall) buildings in Moscow. 4. Copper is (hard) and (strong) than aluminium. 5. Is it (interesting) to study at university than at school? 6. Steel is (heavy) than (aluminum) and (flexible) than steel. 7. What is (expensive) material in the world? 8. The new transistor is (powerful) than the old one. 9. Metal is (strong) than plastic. 10. Nitrogen is (abundant) gas in the atmosphere.