[A] He has been in the army for two years, (todavía está en el ejército); I have smoked since I left school, (todavía fumo); We have waited all day, (todavía estamos esperando); He has lived here all his life, (todavía vive aquí); He has always worked for us, (todavía trabaja para nosotros). He was in the army for two years, (no está en el ejército ahora); I smoked for six months, (y entonces dejé de fumar); He lived here all his life, (presumiblemente está ahora muerto). [B] ANN: (on meeting someone): I haven’t seen you for ages, (pero te veo ahora); This room hasn’t been cleaned for months, (pero la estamos limpiando ahora); It has been very cold lately but it’s just beginning to get warmer. [C] I have known him for a long time; I have never believed their theories. Did you know that he was going to be married? («Have you known» no sería posible); Hello! I didn’t know you were in London. How long have you been here? I have sometimes thought that I should have emigrated; I have often wondered why he didn’t marry her. [D] How long have you been here? – I’ve been here six months. Have you been to the zoo/the theatre/the museums/the casino? Have you enrolled in a school/found a job/met many people? Yes, I have (been to the zoo etc.), o bien: Yes, I went there last week; No, I haven’t enrolled yet, o bien: Yes, I enrolled on Monday/this morning.
Las expresiones de tiempo incluyen «for,» «since, «all day»/»night»/»week,» «all my» etc. «life,» «all the time,» «always,» «lately,» «never,» «recently.»
[A] La acción usualmente comienza en el pasado y continuará más allá del tiempo en que se habla en el presente:
- He has been in the army for two years. (Todavía está en el ejército.)
- I have smoked since I left school. (Todavía fumo.)
- We have waited all day. (Todavía estamos esperando.)
- He has lived here all his life. (Todavía vive aquí.)
- He has always worked for us. (Todavía trabaja para nosotros.)
Este tipo de acción podría representarse por medio de un diagrama de esta forma:
/_____________________________________TS_________________________
Comparar las oraciones de arriba con:
- He was in the army for two years. (No está en el ejército ahora.)
- I smoked for six months. (y entonces dejé de fumar)
- He lived here all his life. (Presumiblemente está ahora muerto.)
En cada uno de los últimos tres ejemplos tratamos con un periodo completado de tiempo:
/_______________________________________/………………………………….TS
de modo que se usa el pasado simple.
[B] A veces la acción termina en el momento en que se habla:
- ANN: (on meeting someone): I haven’t seen you for ages. (pero te veo ahora)
- This room hasn’t been cleaned for months. (pero la estamos limpiando ahora)
- It has been very cold lately but it’s just beginning to get warmer.
Este tipo de acción puede representarse por medio de un diagrama así:
/_______________________________________TS
[C] Los verbos de conocer, creer y entender no pueden usarse en el pretérito perfecto excepto como se indica en [A] arriba (si la acción comenzó en el pasado y se extiende más allá del momento en que se habla):
- I have known him for a long time.
- I have never believed their theories.
Las acciones recientes, incluso cuando no se especifica el tiempo, tienen que expresarse en el pasado simple:
- Did you know that he was going to be married? («Have you known» no sería posible) y
- Hello! I didn’t know you were in London. How long have you been here?
Con think y wonder el pretérito perfecto es posible acompañado de «never,» «always,» «occasionally,» «often,» «several times» etc.:
- I have sometimes thought that I should have emigrated.
- I have often wondered why he didn’t marry her.
[D] Notar que preguntas/respuestas como:
- How long have you been here? – I’ve been here six months.
irán normalmente seguidas de preguntas de caracter general formuladas en pretérito perfecto sobre acciones que ocurren dentro del periodo mencionado, que es visto como un periodo incompleto de tiempo:
/………………………………………………………………TS
porque la acción de permanecer, estar etc., no está aún terminada:
- Have you been to the zoo/the theatre/the museums/the casino?
- Have you enrolled in a school/found a job/met many people?
Las respuestas irán también en pretérito perfecto si no se menciona tiempo, en otro caso estarán en pasado simple:
- Yes, I have (been to the zoo etc.), o bien
Yes, I went there last week.
- No, I haven’t enrolled yet, o bien
Yes, I enrolled on Monday/this morning.
A Practical English Grammar (A.J. Thomson & A.V. Martinet) 