Can 'could have done', 'couldn't have done, 'can have done' or 'can't have done' be used with reference to the future?

‎1.The spaceship couldn't have reached the correct altitude by the time the rockets separate from it.

2.The spaceship could have reached the correct altitude by the time the rockets separate from it.

3.The spaceship can't have reached the correct altitude by the time the rockets separate from it.

4.The spaceship can have reached the correct altitude by the time the rockets separate from it.

Q1) Are all four sentences correct?

Q2) Can 'could have done', 'couldn't have done, 'can have done' or 'can't have done' be used with reference to the future?

2 Answers

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  • 2 months ago
    Favourite answer

    I don't think so. I'd rewrite them: "The spaceship 'could reach' the correct altitude by the time the rockets separate from it."

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  • Laurie
    Lv 7
    2 months ago

    Yes and no. “Done” is PAST tense. Therefore the phrases you ask about look BACKWARD, not forward, in time.

    However, “done” can refer to the future if the main action is even farther in the future, looking back. For example...

    “When I am 80 years old, I don’t want to regret what I ‘could have done’ (when I was younger).”

    In every example you provide, this is what you are doing. The rocket separation occurs AFTER the altitude is reached, so you are looking back in time, but from FUTURE perspective.

    • Englishlove2 months agoReport

      Then are my sentences correct from the perspective?

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