Hey there! I'll try to provide you with my best answer.
Answer:
1. Make sure that your time is spent usefully or you will regret. (use)
2. A visit to the countryside will be beneficial to his health. (benefit)
3. It’s an interesting boy. We all are interested in talking to him. (interest)
4. One disadvantage of living in the city is that the air is so polluted. (advantage)
5. Newton was one of the greatest invention in the world. (invent)
6. Those companies have been completely computed since last year. (computer)
7. She is always in disagreement with us. We don’t like talking to her. (disagree)
8. Parents should choose educational softwares for their children. (educate)
9. Mr. Hoang has worked as a computer programmer for over two years. (program)
10. I’m very thankful to Mrs. Hoa, who has helped a lot with my study. (thank)
11. Some streets in this area are being widened, so traveling is very hard. (wide)
12. The internet is not accessible in some remote areas of this country. (access)
Hope it helps! ^^