When should we use present perfect tense?

Related questions

1. What is the structure of present indefinite tense?
2. What does present perfect progressive mean?
3. What is the past progressive?
4. What is the past perfect progressive?
5. When Use present perfect progressive?
6. What is simple and progressive aspect?
7. What are Progressive perfect verbs?
8. Can we use ago with present perfect?
9. Which helping verb is used in future perfect tense?
10. Is ago an adverb of time?

Tags

1. #fixed
2. #continue
3. #usually
4. #stative
5. #habits
6. #often
7. #unfinished
8. #tense
9. #april
10. #states
11. #started
12. #present
13. #since
14. #verbs
15. #about
16. #actions