El infinitivo de perfecto

[A] Forma

      to have + participio de pasado: to have worked, to have spoken

[B] Uso con los verbos auxiliares

1 Con was/were para expresar un plan o un proyecto que no se llevó a cabo:

• The house was to have been ready today. (pero no está lista) 

2 Con should, would, might, y could para formar el condicional de perfecto:

• If I had seen her I should have invited her. 

3 Con should u ought para expresar obligación no realizada; o bien, en la negativa, una acción equivocada o necia:

• He should have helped her. (pero no la ayudó)
• I shouldn’t/oughtn’t to have lied to him. (pero le mentí)

4 Con should/would like para expresar un deseo no realizado:

• He would like to have seen it. (pero no fue posible) o bien:

   He would have liked to see it.

i.e. podemos poner cualquiera de los dos verbos en el infinitivo de perfecto sin cambiar el significado.

5 Con could para expresar capacidad no utilizada pasada o posibilidad pasada:

• I could have made a lot of money. (pero no hice un montón de dinero)
• He could/might have phoned her. (Perhaps he (has) phoned.) 

6 Con migh/could para indicar que el hablante se siente transtornado o indignado ante la no realización de una acción:

• He might/could have told me! =

= I am annoyed that he didn’t tell me.

7 Con may/might en especulaciones acerca de acciones pasadas:

• He may/might have left = It is possible that he (has) left.
• You might/could have been killed! 

8 Con can’t/couldn’t para expresar deducción negativa.

• He can’t/couldn’t have moved the piano himself. 
• We knew he couldn’t have paid for it, because he had no money

9 Con must para expresar deducción afirmativa:

• He must have come this way; here are his footprints.

10 Con needn’t para expresar una acción pasada innecesaria:

• You needn’t have hurried. Now we are too early.
• You needn’t have cooked it. We could have eaten it raw.

[C] Con algunos otros verbos

1 Con appear, happen, pretend, seem

Notar la diferencia entre los infinitivos de presente y de perfecto aquí:

Infinitivo de presente:

• He seems to be a great athlete = It seems that he is …
• He seemed to be a great athlete = It seemed that he was … 

Infinitivo de perfecto:

• He seems to have been … = It seems that he was …
• He seemed to have been … = It seemed that he had been …

i.e. la acción del infinitivo de perfecto es una acción anterior; ocurre antes del tiempo del verbo principal. Otros ejemplos:

• I happened to have driven that kind of car before =

= It happened that I had driven that kind of car before.

• He pretended to have read the book =

= He pretended that he had read it.

2 Con los siguientes verbos en la voz pasiva: acknowledge, believe, consider, find, know, report, say, suppose, think, understand:

• He is understood to have left the country.

3 El infinitivo de perfecto es posible pero menos usual con claim, expect, hope, promise:

• He expects/hopes to have finished by June =

= He expects/hopes that he will have finished by June.