Past Simple Vs Present Perfect

1. Use Past Simple

1.1. Finished past actions saying the date when happened: "I bought a new car last week"

2. Present Perfect or Past Simple

2.1. Use Present Perfect when we don´t specify a time: "I´ve eaten boiled eggs"

2.2. Use Past Simple when the time is mentioned or understood: "I went to the beach last summer"

2.2.1. Past time expressions: yesterday, last year, etc

3. Uses Present Perfect

3.1. Past experiences without saying the date, often use ever and never: "I´ve never been in England"

3.2. Recent past actions with focus on the present result and use just: "I´ve just lost my card"

3.3. With yet and already: "I haven´t eaten yet" and I´ve already had a bath".

4. Position Present Perfect

4.1. ever, never and just: before the main verb

4.2. already: affirmative sentences and before the main verb

4.3. yet: negative and interrogative sentences goes at the end

5. Structure Present Perfect

5.1. Affirmative: Subj + have/has + past participle (regular verb -ed / third column of irregular verb)

5.2. Negative: Subjt + have/has not + past participle

5.3. Interrogative: have/has + subjt + past participle