23. costly (adj): tốn kém

24. documentary (n): phim tài liệu

25. presevationist (n): người bảo vệ, ủng hộ

26. environment (n): môi trường

27. innovate (v): đổi mới

28. scientifically (adv): một cách có cơ sở khoa học

29. effectively (adv): một cách có hiệu quả

30. consumed (V-Pii): tiêu thụ

23. It is still a bit _____costly______ to use the Internet in everyday life. ( cost ) 
24. They showed a _____documentary______about animal communication. (document) 
25. She is one of the most active ______presevationist________ of the campaign. (preserve)
26. Certain chemicals have been banned because of their damaging effect on the ____environment_____. (environmentalist) 
27. The fashion industry is always desperate to _____innovate_______. (innovation)  
28. It is ___scientifically ____proven that there is a relationship between lung cancer and smoking. (science)  
29. The new method enables us to do our jobs ____effectively____. (effect)  
30. We recommend that this wine should be ____consumed______ within six months.  (consumption)