what's different in meaning between these two sentences?

  1. The decorator will have painted the wall by Thursday.
  2. The decorator will paint the wall until Thursday.

Does the second sentence mean the decorator will finish painting exactly before Thursday start or it could finish before for example in Wednesday like Future Prefect Tense.

  • The second sentence makes it sound like the decorator will, without break, continue to paint the wall until Thursday morning.
    – Freddie R
    Commented Oct 22, 2018 at 12:34
  • Careful with the text prediction - prefect?
    – microenzo
    Commented Dec 21, 2018 at 18:31

2 Answers 2


Sentence #1 means that on Thursday, we can expect the work of painting the wall to be completed, regardless of the exact time at which the decorator stopped.

Sentence #2 means that the decorator will be painting until Thursday and then stop, with no indication either way on whether the work will actually be "finished" at that point.

Both sentences have a degree of ambiguity on whether Thursday is included in the scope of the work - see this question on ELL about inclusive/exclusive "until", and this one on "by" when used with dates.


The essential difference is:

The perfect tense defines a time space between Now and Thursday, and then states that the main action will complete before the end of the period. Whether this finish time of the period and hence the painting includes part of Thursday is not defined, so the painter could still be painting on Thursday morning. It also does not define anything about whether then painting will be done in one long chunk or in stages, it is only the conclusion of the action before the finish that is important.

The simple tense merely states that the action will take place, and then states that this period starts Now (will) and completes sometime on Thursday (until), with the proviso that 'until' implies that the poor painter will continue painting 24 hours a day.

  • Until doesn't imply anything about 24 hours a day, just that he'll be painting during normal painter work hours. Commented Apr 20, 2019 at 17:35
  • Normal painter work hours is an assumption with no basis in the sentence. This is one of the problems with teaching by context-free phrase comparison, failing to remember that the grammar will work at its most base level: what you see is all you have. Like you I would not have considered this in the past, but having spent several decades proofreading translations done by people with language degrees, I can see that many of the problems comes from this lack of consideration. As a former co-worker once said: "articles must be easy, they take so little room in grammar books". Commented May 8, 2019 at 11:12
  • Grammar does not work independently of the real world. If you say "I have been working constantly towards this goal for the last two years", it does not mean 24 hours a day, to the exclusion of sleeping, eating, and going to occasional movies. Here, until means he is doing as much painting as is reasonable to expect of him. It does not mean 24 hours a day. Commented May 8, 2019 at 11:33
  • But sometimes until does indeed mean 24 hours a day. If you say the road will be closed until August, nobody should expect they can drive on it between 10pm and 5am. Commented May 8, 2019 at 11:37

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.