Restorers have returned the Leaning Tower of Pisa to its former glory after an eight-year restoration project in which they cleaned and partially straightened it.

Workers were using chisels and hi-tech laser technology to scrub grime from the more than 24,000 blocks of stone on the 183ft tall tower.

that was the solution given to that exercise but

Could we use have cleaned and have straightened if the restorers have returned, it shows that the restoration has been finished very recently and could it be the same with "workers have been using "instead of "workers were using" https://www.grammar-quizzes.com/presperf1b.html

  • Hi user5577, in my opinion, using either "cleaned"/"straightened" or "have cleaned"/"have straightened" in the first sentence is fine and implies that the work is complete (but doesn't tell you whether it was finished very recently or finished a long time ago). If you use "have straightened" it should be split either side of the "partially" to flow well - e.g. "....restoration project in which they have cleaned and have partially straightened it". For the second sentence, I believe it's better to say "Workers used chisels..." rather than "were using",
    – Paul
    Jan 29, 2020 at 12:54
  • 1
    as it makes the verb tense consistent with the first sentence. "Were using" still implies past action, but to me it implies that there is a conjunction or extra information that is missing. For example ("Workers were using chisels and hi-tech laser technology to scrub grime from the more than 24,000 blocks of stone, but eventually switched to sandblasting due to schedule constraints"). Just for clarity, the "have returned" in the first part of the first sentence is talking about the building, not the workers,
    – Paul
    Jan 29, 2020 at 12:56
  • so there is nothing in either of the sentences that tells us that the works have returned to the site recently (or at all) - apologies if this was already clear!
    – Paul
    Jan 29, 2020 at 12:59
  • There's a "tense clash" between your first and second sentences, because for #1 the "narrative reference time" is now, time of utterance (after the restoration has been completed), whereas for #2 the narrative reference time is in the past (during the restoration process). That's not necessarily a "syntactic error", but imho it's clumsy and confusing for the reader. Jan 29, 2020 at 14:01
  • 2
    The eight years is finished. The simple past is fine.
    – Lambie
    Mar 6, 2020 at 16:09

2 Answers 2


As far as I know, one uses the present perfect to emphasise actions that would otherwise be described in the simple present. According to the material given, the upgrading works are complete. This means that any description of the works will be in the past tense.

When the material says “were using”, it is really just emphasizing that they “used chisels and hi-tech laser...” to do whatever was necessary. If you said “have been using”, it would sound like the upgrading was still work in progress and thus incomplete.


It's not quite right to say "in which they have cleaned..."

"an eight-year restoration project in which..." establishes a completed, past time frame as the time sense of what follows. During this time frame, the cleaning and straightening were not yet done, so simple past tense makes much more sense here.

Compare with:

During my college years, I smoked cigarettes. (correct)

"During my college years, I have smoked cigarettes." (incorrect)

The time sense of this sentence is the same as that of the preposition starting with "in" above.

"During the restoration project, they cleaned and partially straightened it." (correct)

"During the restoration project, they have cleaned and partially straightened it." (incorrect)

"...after an eight-year restoration project in which they have cleaned and partially straightened it." (incorrect)

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