Um pequeno resumo sobre as present tenses

1. Present tenses

2.  When we study the present tenses, there are three
forms used in English:
 Present Simple
 Present Continuous
 Present Perfect

3. Examples
1. Present Simple:
It´s used for habits and states.
Ex.: I work every weekend.
2. Present Continuous:
It´s used for actions in progress and for future arregements.
Ex.: I´m having dinner;
She´s not coming tonight.

4. 3. Present Perfect:
It´s used in three specific cases:
3.1: Past experiences without a specific time.
Ex.: I´ve never been here before.
3.2: Completed actions from a past point in time to now.
Ex.: We´ve just eaten.
3.3: Unfinished past: actions / states that began in the past and
continue until now.
Ex.: She has had three dates since she started speed dating.