B2 · temario
4.11tema 11 de 16

Modals of Deduction (Past)

Deducir sobre el pasado: must/might/can't have + participio

Los modales de deducción sobre el pasado son como un depurador que analiza un log: no viste lo que pasó, pero deduces por las pistas. Según tu grado de certeza usas un modal distinto + HAVE + PARTICIPIO. Es como asignar un nivel de confianza a una hipótesis sobre un evento pasado que no presenciaste.

MUST HAVE + participio expresa CERTEZA lógica: estás casi seguro de que algo ocurrió. 'The ground is wet — it MUST HAVE rained.' No lo viste, pero la evidencia es contundente. En español sería 'debe de haber llovido'. El error del hispanohablante es olvidar el HAVE o usar 'must rained'.

MIGHT HAVE / COULD HAVE + participio expresan POSIBILIDAD: no estás seguro. 'She's late — she MIGHT HAVE missed the train.' Es una hipótesis abierta, no una conclusión firme. CAN'T HAVE / COULDN'T HAVE + participio expresan IMPOSIBILIDAD: estás seguro de que algo NO ocurrió. 'He CAN'T HAVE finished already — it's impossible.'

Ojo con la trampa NEEDN'T HAVE DONE vs DIDN'T NEED TO DO. 'You needn't have cooked' = cocinaste, pero no hacía falta (acción realizada innecesariamente). 'You didn't need to cook' = no hacía falta cocinar (y quizás no lo hiciste). El matiz es sutil: needn't have implica que SÍ se hizo la acción inútilmente; didn't need to solo dice que no era necesaria.

structure.txt
CERTEZA:      MUST HAVE + PAST PARTICIPLE
  It must have rained; the streets are wet.

POSIBILIDAD:  MIGHT / COULD HAVE + PAST PARTICIPLE
  She might have forgotten the meeting.
  They could have taken the wrong turn.

IMPOSIBILIDAD: CAN'T / COULDN'T HAVE + PAST PARTICIPLE
  He can't have finished; he only just started.

MATIZ:  NEEDN'T HAVE DONE  vs  DIDN'T NEED TO DO
  You needn't have paid. (lo pagaste, pero no hacía falta)
  You didn't need to pay. (no hacía falta pagarlo)

Debugging lab

Corrige o completa la línea. 7 ejercicios por tema.

0/11 tests passing0%
  1. 4.11.6.1

    The lights are off — they must left already.

  2. 4.11.6.2

    She's not answering; she might forgotten her phone.

  3. 4.11.6.3

    You mustn't have seen her yesterday; she was in Paris.

  4. 4.11.6.4

    He can't have passed the exam without studying.

  5. 4.11.6.5

    You needn't have cook dinner; we already ate.

  6. 4.11.6.6

    They could have taken the wrong exit on the highway.

  7. 4.11.6.7

    I didn't needed to bring an umbrella; it was sunny.

  8. 4.11.6.8

    The ground is wet — it must rained last night.

  9. 4.11.6.9

    She's late — she might missed the train.

  10. 4.11.6.10

    He mustn't have finished already — it's impossible.

  11. 4.11.6.11

    You needn't have bought milk — we already had some.