I know that "could have +past participle" and "couldn't have +past participle" have different meanings when we use them in Declarative sentences, but I think when we use them in Interrogative sentences they have the same meaning. Am I right? Examples: Could you have been nicer at the party? couldn't have you been nicer at the party?

  • pp: present perfect Sep 9, 2016 at 19:38
  • Examples: Could you have been nicer at the party? couldn't have you been nicer at the party? Sep 9, 2016 at 20:55
  • We do not use more with adjectives which end in -er or -est. See this link. Sep 9, 2016 at 21:00
  • PP (note case!) == past participle. Can you add example sentences to illustrate your question? Do you mean "could +present perfect" e.g. "could have driven"? Sep 9, 2016 at 21:02
  • @Cardinal Your edit incorporated my mistaken edit! The OP intended present perfect, and I misunderstood it. Perhaps we can persuade him to add some examples... Sep 9, 2016 at 21:06

1 Answer 1


couldn't have in the interogative implies that I think you could have.

could have does not indicate my opinion.

"Couldn't he arrive earlier?" means I think you could arrive earlier next time, and I am asking you if I am correct.

"Could he arrive earlier?" means I do not necessarily have an opinion on whether he will be able to arrive earlier.

This is true for in general for negative interrogatives. They imply my opinion, and are often used to disagree with someone.

"Shouldn't I talk to John?" Means I think I should talk to John, but I want your opinion.

"If I go to London, should I visit Buckingham Palace?" is neutral. I am not expressing my opinion.

  • Dear some-guy:what about " could you have arrived earlier?" Sep 10, 2016 at 3:50
  • @MehrdadMoshaver It is more likely that you would say "couldn't you have arrived earlier?", which means "I think you could have arrived earlier, what do you think?". Could you have arrived earlier means literally "is it possible that you were able to arrive earlier?".
    – Some_Guy
    Mar 30, 2017 at 16:02

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