1. Because of the shortage of water, we should use it very ___ (effect) 2. Saving money is ____ to all of us. (profit) 3. ______ from his friends made him sad. (separate) 4. Have you ever met Susan ______? (recent) 5. You should always try to behave quite _______ (ordinary) 6. Scientist succeeded in _______ oxygen. (solid) 7. Susan won the prize for _____ of attendance at school last month. (regular) 8. He is responsible for the heating ______ of this building. (install) 9. Energy-saving bulb should be used to save _____. (electrify) 10. A _____ is the person who installs and repairs thing such as water pipes, toilets, etc....(plumbing) 11. To keep the air unpolluted, people ought to use ____ energy to create electricity. (sun) 12. There have been many ____ in the field of electrical engineering.(innovate) 13. Televisions, dishwashers and freezers are electrical ____. (apply) 14. No doubt that there will be a great ______ of food for the world's population. (short) 15. If there is something wrong with the lights, ask an _____ to look at it. (electric) 16. An old friend of mine felt amazed at the prize for her efforts at ____ in her country. (conserve)