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Which of these should I use?

My test result should be done by last Wednesday.

or

My test result should have been done by last Wednesday.

What is the difference in meaning?

tchrist
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INGO
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2 Answers2

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Because you’ve specified last Wednesday, you need a completed action:

  • My test result should have been done by last Wednesday.

If we’re talking about a future event, you need the other version:

  • My test result should be done by next Wednesday.
tchrist
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  • The first part of this answer is correct; the second part not so. "My test result should have been done by next Wednesday" means that you are under an obligation to do it by then. "My test result should be done by next Wednesday" is ambiguous and its primary meaning is that you hope or expect that it will be done. – Channel Islander Jul 26 '15 at 19:32
  • @ChannelIslander Elaborate. – tchrist Jul 26 '15 at 19:32
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    At least in British English, should have been done can be used for completed-in-the-future: "My test results should have been done by next Wednesday, because I have been asked to pick them up then." Your "need" could be "can use". But perhaps AmE is different. [I was going to migrate this question. But I won't now.] – Andrew Leach Jul 26 '15 at 19:39
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    @AndrewLeach That’s . . . curious. There’s something about that which feels very weird to me. I can say "will have been done by next Wednesday" or even "would have been done by next Wednesday". But I cannot use should or must instead of will or would there. It feels like it's trying to be in two times at once or something otherwise. Very odd. On the other hand, "It should have been done already" is just fine. – tchrist Jul 26 '15 at 19:45
  • But should implies some doubt (whereas will implies certainty). Would implies a condition. So as "will have been done by next Wednesday" is definite, to water that down to merely probable requires "should have been done by next Wednesday". – Andrew Leach Jul 27 '15 at 06:19
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It sounds like the test result should've been done prior to last Wednesday. With something happening prior to a time in the past ( last Wednesday), had is operative term to use; however, it also sounds like the test result still is not done in the present time. Have and has are used to refer to things in the past that are in the present as well.

My test result should have had been done by last Wednesday, but it still is not.

I added the last part so that it's clear that the result was not done on time and is still not done in the present time.

Dunnup
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