11. This novel is not ....................... of all his works. (represent) 12. The outbreak of the flu epidemic resulted in a sharp........in the number of tourists. (reduce) 13. Recycling programs have helped to solve some of the........problems. (environment) 14. These plants grow well in .......... soil by the river. (fertilize) 15. This book is very interesting; it contains lots of information. (use) 16. The river has been used for many years as a waste dump.(industry) 17. All of the students in my class elected Huong as our......... (represent) 18. The silence and....... of the house made the children feel frightened. (empty) 19. Farmers use different kinds of ...........to enrich the soil. (fertilize) 20. We are very surprised at the speed of the .........of the city. (industrial) 21. Companies are encouraging people to buy more by .......the prices of their products. (reduce) 22. The money should be more .........spent on the recycling plan. (use)