IF YOU SAY YOU HAVEN´T SUFFERED WITH THESE TWO TENSES, I DON´T BELIEVE YOU

Present Perfect vs Past Simple

                                                                  see this chart I´ve found at 7esl

Consider that one of the most important differences between them is that with the Present Perfect you don´t know WHEN the action happened or you DON´T WANT TO SAY IT . 

Past Simple and Present Perfect Differences in Form

• Past Simple Tense:

S + V in the 3rd column 

• Present Perfect Tense:

S + have/ has + V in the 3rd column

Present Perfect and Past Simple Differences in Usage

• The past simple tense is used to express finished time; In contrast, the present perfect tense describes unfinished time.

Examples:

We lived Japan in from 1995-1998. (a time period that started and ended in the past) (past simple)

I’ve worked as a teacher since 2011. (a time period that started in the past, and continues until now) (present perfect)

• The past simple tense is used to refer to definite time, while the present perfect tense refers to indefinite time.

Examples:

I saw the Eiffel Tower in 2007. (past simple)

I have seen the Eiffel Tower. (present perfect)

• The past simple tense indicates series of finished actions or repeated actions; the present perfect tense expresses experience or result.

Examples:

First, he read book and then he watched movie. (past simple)

He went to the cinema every weekend last year. (past simple)

Have you ever seen this movie? (present perfect)

She has already watched this movie 3 times. (present perfect)

Time Phrases for Past Simple vs Present Perfect

Past Simple Tense

Yesterday

Ago

Last

In 1994, etc.

In the 20th century,etc.

In July, etc.

On Monday, etc.

…

Present Perfect Tense

Already

Just

Yet

Ever

Never

For

Since

You will need to study the three columns of verbs: infinitive, simple past and past participle. For example: 

go  -  went  - gone

work  - worked  -  worked