"as" or "when"?


Senior Member
...because they needed to think quickly as they pursued their prey.​
This sentence's subject is "a small kind of dinasaur." Is it perfectly all right to replace "as" with "when"?

Are there any differences between the two?
  • Old Novice

    Senior Member
    USA, English
    To me, "as they pursued" describes actions during the actual moments of a pursuit, while "when they pursued" describes habitual behavior during pursuits. But I have no idea if anyone else would agree.


    British English
    Yes, you're right - I'd not thought of that. But on reflection I wonder if that distinction applies in this example, which relates to "a small kind of dinosaur", suggesting to me the "habitual behaviour" case, and not a particular pursuit.


    Member Emeritus
    British English
    Yes, Fredsie, I think your idea is right, given the context which appears to be a general description of a kind of dinosaur. Otherwise it would be 'while'.