In Advanced Grammar In Use, Unit 20, there's this:
We also use should have + past participle to talk about an expectation that something happened, has happened, or will happen:
(1) If the flight was on time, he should have arrived in Jakarta early this morning.
(2) The builders should have finished by the end of the week.
I believe that (1) corresponds to "an expectation that something happened", and that (2) "an expectation that something will happen".
Am I right?
If so, "the week" refers to this week, and "the end of the week" a future time.
Assuming that "the end of the week" refers to a future time, do these variations of (2) work?
(2a) The builders should finish by the end of the week.
(2b) The builders should finish at the end of the week.
(2c) The builders should have finished at the end of the week.
EDIT
Having read the answers by Evelyn and RuslanD, I now know (2c) is not natural English. How about these alternatives?
(2d) The builders should have finished before the end of the week.
(2e) The builders should have finished at or before the end of the week.
(2f) The builders should have finished within the end of the week.
(2g) The builders should have finished the end of the week.
Or can you think of some other preposition that works in this sentence?
Best Answer
1) Right. You don't know whether the plane was on time or some other factor intervened, but you fully expected him to arrive in Jakata this morning and have no reason to think he didn't.
2) Also right (mostly). "The week" is the present week, and "the end of the week" is yet to come (unless right now happens to be 5:00 pm on Friday, or midnight on Saturday, or whatever other time has been defined as the end of the week).
In 2) & 2a), "by" means "at or before," so the builders are expected to be done sometime between now and the end of the week.
In 2), the past perfect implies prior completion, so it means you expect the builders to have finished the work, swept up the debris, and left the site well before 5:00 pm on Friday (which I'm going to define as the end of the week for the purposes of this answer).
2a) is the simplest construction here, and the present simply means that you expect the builders to finish the work at or before 5:00 pm on Friday.
In 2b), "at" means "at (that moment)" so it would most strictly mean that you expect the last nail to be driven home at exactly 5:00pm on Friday. But, depending on context, "at" usually carries some leeway to either side of the time specified (perhaps especially so in the context of builders).
2c) is the only one that doesn't quite work. The prior completion of the past perfect and the immediacy of "at" are at odds with each other. It's not very wrong, but does sound off and it's not something I would say unless by accident.
(My landlord's got builders working at my apartment right now. They're not supposed to have finished until the end of week after next (that is, about two-and-a-half weeks from now), and there's a good chance they won't be done even by then.)