Presente perfecto ingles

Formas el present perfect de la manera siguiente:
Subjeto + have/has + participio
|I |have  |worked |
|You |have |seen |
|She |has|walked |
|He |has |spoken |
|It |has |rained |
|We |have |forgotten |
|You |have|worn |

Uso del Present Perfect

|Por qué el Present Perfect? |Ejemplos ||Para hablar de una acción del pasado sin decir cuando (sin expresión de tiempo) |I have visited Rome |
||I have seen him twice |
|Para hablar de una acción que empezó en el pasado y continua en el presente |I have been ill for 3 days|
| |They have been married for 10 years |
|El present perfect se usa a menudo conlas siguientes palabras: already, yet, just, |She has just bought a new car |
|since, so far |I have alreadymade my bed |
| |We haven’t cleaned the kitchen yet |
||You haven’t visited me since March |
||I have been to the cinema once so far this month |
|Cuando una acción es tan recién que aún notas las consecuencias |It smells funny in here: oh look, they have |
|...