15. have studied
16. wouldn't
17. listening
18. was introduced
19. friendly
20. enjoyable
21. modernize
22. impressively
15. We have studied in this school for three years.
16. I wish it didn't rain.
17. She enjoys listening to music in her free time.
18. A new style of jeans was introduced in the USA last year.
19. She was really impressed by the friendliness of Vietnamese people.
20. We had an enjoyable picnic in the Botanical Garden.
21. The government should modernize the system of traffic.
22. The band performed very impressively in the concert last night.
