1. Structure
1.1. affirmative
1.1.1. pro(noum)+have/has+past participle
1.1.1.1. I have done my breakfast
1.2. negative
1.2.1. pro(noum+haven't/hasn't+past particple
1.2.1.1. I haven't done my breakfast
1.3. interrogative
1.3.1. have/has+pro(noum)+past participle
1.3.1.1. Have you done your breakfast?
1.4. short answer
1.4.1. affirmative
1.4.1.1. Yes, I have
1.4.2. Negative
1.4.2.1. No, I haven´t
2. Use
2.1. actions that still continue
2.1.1. She has worked as a teacher since 2006
2.2. recentily finished actions
2.2.1. I have broken my leg
2.3. experiences
2.3.1. She has tried hiking
2.4. actions which happened at an unspecified time in the past
2.4.1. Peter has bought a new car
3. Adverbs
3.1. just
3.1.1. I have just eaten
3.2. so far
3.2.1. I have eaten sushi three times so far
3.3. ever
3.3.1. Have you ever eaten sushi?
3.4. never
3.4.1. I have never eaten sushi
3.5. already
3.5.1. I have already eaten
3.6. yet
3.6.1. I haven't eaten yet
4. Preposition
4.1. since
4.1.1. from a starting point in the past
4.1.1.1. I haven't eaten sushi since last year
4.2. for
4.2.1. over a period of time
4.2.1.1. I haven't eaten sushi for three years
5. Past Participle
5.1. regular verbs
5.1.1. We form past participle of regular verbs by adding -ed to the verb
5.1.1.1. wash-washed
5.1.1.2. clean-cleaned
5.1.1.3. study-studied
5.2. irregular verb
5.2.1. We form the past participle of irregular verbs differently (see an irregular verb list)
5.2.1.1. do-done
5.2.1.2. know-known
5.2.1.3. eat-eaten