13. Air and water _______________can make people fall ill. (pollute) 14. We should make our world ___________________. (pollute) 15. You may face a ________________or termination of benefits. (reduce) 16. Without practice, hopes will be _________________to zero. (reduction) 17. She is a very helpful and ____________ woman. (energy) 18. _______________, the student couldn’t answer the examiner’s question exactly. (disappoint) 19. Every citizen may claim the ________________of the law. (protect) 20. Trees should be well _____________from the cold during winter. (protect) 21. The drugs work well at first but gradually lose their ______________. (effective) 22. The company must reduce costs to compete _________________. (effect) 23. Food, clothing and shelter are all basic ________________of life. (necessary) 24. In writing this report, I have omitted all ___________________details. (need) 25. Does that machine work ______________? (effect)