Difference between 'would+present' and 'would have+past participle' in these cases.


When John was 30, the doctor told him that he wouldn't live/wouldn't have lived past 40. Now he's fifty and his health is great.

Correct me if I'm wrong. In this case, I'd choose 'wouldn't have lived' because we know that John, who now is fifty, is alive and in good health. But if we where in a time when John is, say, 32, we would have to use the first, i.e. 'wouldn't live', because there would be still some chance that John wouldn't make it past 40. Am I right?


Mary moved to London because she thought a bigger city would increase/would have increased her job opportunities.

In this case, it depends. If I was writing a story about Mary, and I didn't want to reveal the outcome to the reader, I would use 'would increase'. So, in this case, we don't know if Mary would find a job in London or not. But if both I and the reader knew already that Mary did not find a job in London, I could as well use 'would have increased'.

  • 2
    "Wouldn't live ..." is not 'would+present' but 'would+plain (infinitive).
    – BillJ
    Commented Sep 13, 2022 at 9:38

1 Answer 1


I disagree about Example 1. At the time the doctor spoke to John, he was predicting the future - 'You will not live past 40'.

The doctor told John he would not live past forty.

Would not have is only appropriate when looking back at the possibilities that existed at a point in the past.

Last week, the doctor told John that, if he had not given up smoking in his thirties, he would not have lived past forty.

  • So, I presume you agree about example 2, right?
    – Fra
    Commented Sep 13, 2022 at 9:47
  • 1
    I find that less clear-cut, but on reflection I still think would have fits better with looking back. You would have thought that moving to London would have increased Mary's job opportunities, but it did not. Commented Sep 13, 2022 at 12:02

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