Corregimos el proyecto durante el plazo de subsanación.

Corregimos is the first-person plural form (we) of corregir.

It can mean either:

• we correct / we are correcting (present), or
• we corrected (preterite / simple past)

This form is ambiguous by itself, because the nosotros form of some -ir verbs looks the same in the present and the preterite.

So the exact tense depends on context. On its own, this sentence could be understood as either present or past, although many learners first read it as present.

Spanish often drops subject pronouns when they are not needed.

In corregimos, the ending -imos already tells you the subject is we. So nosotros is optional:

• Corregimos el proyecto...
• Nosotros corregimos el proyecto...

Both are correct, but the version without nosotros is more natural unless you want to add emphasis, contrast, or clarity.

Spanish uses the definite article much more often than English.

El proyecto means the project, referring to a specific project that is already known in the context.

If you said un proyecto, that would mean a project, not a particular one.

So:

• corregimos el proyecto = we corrected/correct the specific project
• corregimos un proyecto = we corrected/corrected a project

Durante usually means during.

It introduces a time period:

• durante el verano = during the summer
• durante la reunión = during the meeting
• durante el plazo de subsanación = during the correction/remedy period

After durante, you normally use a noun phrase, not a conjugated verb.

So this sentence literally has the structure:

• Corregimos = we corrected / we correct
• el proyecto = the project
• durante el plazo de subsanación = during the remedy/correction period

Plazo de subsanación is a formal administrative/legal expression, especially common in Spain.

• plazo = deadline, time limit, period
• subsanación = remedying, correcting, fixing deficiencies or missing information

Together, plazo de subsanación refers to the period allowed to fix errors, submit missing documents, or correct problems in an application, form, project, or official procedure.

It is not especially everyday language; it sounds bureaucratic or official.

It comes from the verb subsanar, which means to remedy, to correct, to fix, or to make good a defect/omission.

This verb is common in formal contexts such as:

• administration
• legal documents
• public applications
• official notices

So:

• subsanar errores = to correct errors
• subsanar una solicitud = to fix/correct an application
• plazo de subsanación = period allowed for correcting deficiencies

Both structures are possible in Spanish, but they are not identical in style.

• plazo de subsanación sounds fixed, formal, and bureaucratic
• plazo para subsanar sounds a bit more verbal and often slightly less formulaic

Compare:

• durante el plazo de subsanación = during the remedy/correction period
• durante el plazo para subsanar los errores = during the period for correcting the errors

In official Spanish, plazo de subsanación is a very common set phrase.

Yes. Corregir can mean to correct, to revise, or to fix errors in something.

With el proyecto, it suggests making corrections or amendments to the project, for example:

• fixing mistakes
• changing incorrect parts
• improving it after feedback
• amending it so it meets requirements

Depending on context, English might translate it as:

• correct
• revise
• amend
• fix

So corregimos el proyecto does not necessarily mean only correcting grammar or spelling; it can be broader.

Yes. Spanish word order is fairly flexible.

You could also say:

• Durante el plazo de subsanación, corregimos el proyecto.

This version puts the time expression first, which can make it sound a bit more natural in some contexts, especially if you want to emphasize when the action happened.

Both versions are correct:

• Corregimos el proyecto durante el plazo de subsanación.
• Durante el plazo de subsanación, corregimos el proyecto.

Because el proyecto is a direct object thing, not a person.

Spanish uses the personal a mainly with specific people (and sometimes personified animals/pets):

• Veo a María. = I see María.
• Corregimos el proyecto. = We correct/corrected the project.

Since proyecto is an object, not a person, there is no personal a.

The original sentence sounds quite formal because of plazo de subsanación.

A more everyday version might use phrases like:

• Corregimos el proyecto dentro del plazo para arreglar los errores.
• Corregimos el proyecto en el periodo para hacer las correcciones.

These are easier to understand for learners, but they may sound less like the kind of wording used in official notices or administrative documents.

So the original sentence is good Spanish, but it belongs to a more formal register.