Present Perfect vs Past simple

Affirmative
I learned to drive in 2016.

Negative
I didn't watch the soccer match last night

Interrogative
Did you eat pizza yesterday?

We use the auxiliary verb only in negative and interrogative forms. When the auxiliary verb is present, the verb is not conjugated.

​Auxiliary "did"

Affirmative
Susan has learned to drive.

Negative
I haven't watched that movie

Interrogative
Have you ever eaten frogs?

We use the auxiliary verb in all three forms, followed always by the past participle form of the verb.

Auxiliary "have / has"

It's used to talk about completed actions in the past.
- She was my girlfriend when we were in college. (She is not my girlfriend anymore)
- Tania worked in this hospital for ten years. (She doesn't work here now)
- Ricardo and Juan died in an accident two years ago.

​Finished actions

It's used to express unfinished events that started in the past and continue up to the present.
- I've lived in Paris for 5 years. (I still live in Paris)
- Sophia has worked here for 2 months. (She still works here)
- Marcus and Julie have been married since 2017. (They are still married)

Unfinished actions

• Isaac Asimov wrote a lot of books

• Rosa Parks was a civil rights activist

• Diego Rivera painted many incredible murals

​Finished events in someone's life (the person is dead)

• My brother has lived in three different countries

• Haruki Murakami has written a lot of books

• My brothers have never travelled by plane
  

Finished events in someone's life (the person is alive)

• I bought a cellphone last week

• I didn't go on vacation last year

• I lost my wallet two weeks ago

​Finished events with no effect in the present

• I have lost my cellphone. (I can't find it)

• She has gone out. (She is not at home right now)

• I haven't found a job. (I'm still looking for a job)
  

Finished events that have an effect in the present

• She went to Paris in 2018

• I had surgery three years ago.

• She visited me last weekend.

​Used with finished periods of time (last year, two years ago, in 1998, etc).

• I haven't had breakfast today.

• They have spent a lot of money this month.

• She has been to Mexico City three times this year.

  
  

Used with an unfinished period of time (today, this week, etc.)