# Why do we use past perfect instead of past tense here?

"We couldn't put down the floor until the plumber HAD finished."

When 'finished' would do the same job much more perfectly instead of confusing.

• Did you check here for other instances of this question? I wonder if the plumber finishing was BEFORE the putting down, so we are talking about two different times, both in the past? Apr 11, 2020 at 23:23
• It seems to be the reported speech of say, They said, “You cannot put down the floor, until the plumber has finished.” In the reported speech, it becomes, They said that we couldn’t put down the floor until the plumber had finished.” If this is not the case, …until the plumber finished… makes sense. Apr 12, 2020 at 0:27
• Note that in actual speech, the difference would be only whether there is a /d/ between the pronunciations of plumber and finished. That would be a cluster of /rdf/, which is not very likely in English. So, whatever your teachers told you, most of the time the difference between past tense and past perfect is irrelevant because it's inaudible, like French plural -s. And native speakers behave accordingly. Feb 1, 2022 at 15:25

In general, both (a) and (b) are possible.

a. We couldn't put down the floor until the plumber finished.

b. We couldn't put down the floor until the plumber had finished.

If you started putting down the floor right after the plumber was done, I think either (a) or (b) works. But (a) is simpler, so you might want to go with (a).

If you didn't start putting down the floor right after the plumber was done, but you waited some time in between, I think only (b) works.

Since we do the flooring and the plumber does the plumbing, the second scenario is more likely to fit the sentence. In that case, (b) is better, despite the more complex form.

First The plumber finished, then we put down.

The plumber had finished. We couldn't put down the floor.

past perfect- past of the past,
simple past- past

• Neither of the two sample sentences makes that much sense in the context of the question. Sep 4, 2021 at 10:17