11. The public service announcement called for volunteers to ______ time to look after the sick in the local hospital. A. donate B. recede C. direct D. fight 12. People often grow flowers and vegetables in a _______. A. green house B. greenhouse C. light house D. lighthouse 13. A flying car can reach 120 km per hour _________. A. in the air B. on the runway C. on the ground D. in the test flight 14. The inventions that ______ animals are the aeroplane and the submarine. A. imitate B. describe C. recognise D. experience 15. The aeroplane is considered one of the greatest inventions in our history because it helps us to travel long distances in the air and encouraged the development of ___. A. life under the sea B. tourism and trading C. people’s lives D. the environment