Rectificamos en la hoja de respuestas.

It can mean either one.

With nosotros forms of regular -ar verbs, the present and the preterite look the same:

• rectificamos = we correct / we are correcting
• rectificamos = we corrected

So this form is ambiguous on its own. The surrounding context tells you which meaning is intended.

For example:

• Ahora rectificamos en la hoja de respuestas. = Now we correct on the answer sheet.
• Ayer rectificamos en la hoja de respuestas. = Yesterday we corrected on the answer sheet.

Here, rectificar means something like to correct, to amend, or to make a correction.

It is related to the idea of putting something right after a mistake or after reconsidering it.

A useful warning: although English has the verb to rectify, Spanish rectificar is often used more naturally and more often than English rectify in everyday situations. So in many contexts, the best English translation is simply correct or amend, not necessarily rectify.

Both verbs can involve correction, but they are not always identical.

• corregir = the more general and very common verb for to correct
• rectificar = often to amend, to revise, to correct what was said/written, or to put right

In an exam context, corregir is often the more everyday choice if you mean to correct answers or to mark work.

So:

• Corregimos las respuestas = We correct the answers / We mark the answers
• Rectificamos can suggest we make a correction or we amend what was written

This sentence is understandable, but depending on the exact situation, a native speaker might more naturally say corregimos.

Because Spanish often leaves out the direct object when it is already clear from the context.

The sentence does not explicitly say what is being corrected. That could be understood from the situation, for example:

• the answers
• a mistake
• something previously written

A fuller version could be:

• Rectificamos las respuestas en la hoja de respuestas.
• Rectificamos el error en la hoja de respuestas.

So the original sentence is not ungrammatical; it is just less explicit.

Because en is the normal preposition for saying where something is written or done.

Here it means:

• on the answer sheet
• literally, sometimes in/on the answer sheet, depending on how English would phrase it

Spanish uses en in many cases where English prefers on:

• en la página = on the page
• en la pizarra = on the board
• en el papel = on the paper

So en la hoja de respuestas is the natural way to say that the correction is made on the answer sheet.

Because la refers to a specific answer sheet that both speaker and listener are expected to know about.

In exam or classroom contexts, there is usually one particular sheet being discussed, so Spanish normally uses the definite article:

• la hoja de respuestas = the answer sheet

If you said una hoja de respuestas, it would mean an answer sheet or a certain answer sheet, which sounds less specific.

Because it means one sheet that contains multiple answers.

So:

• hoja = one sheet
• respuestas = several answers

This is very natural in both Spanish and English:

• hoja de respuestas = answer sheet
• literally, sheet of answers

The structure noun + de + noun is extremely common in Spanish.

Yes, it is a normal and understandable expression in exam or test contexts.

In Spain, hoja de respuestas is a natural way to refer to an answer sheet, especially when answers are written separately from the question paper.

Depending on the context, you might also hear things like:

• la hoja del examen = the exam sheet
• la hoja de respuestas = the answer sheet
• el cuadernillo = the test booklet

So hoja de respuestas is perfectly fine, especially when you want to be specific about the sheet where the answers go.

It could be, but it depends on the intended meaning.

If the idea is we are making a correction on the answer sheet, it works.

However, in some classroom situations, a Spanish speaker might say something more natural such as:

• Corregimos en la hoja de respuestas.
• Hacemos la corrección en la hoja de respuestas.
• Rectificamos las respuestas en la hoja de respuestas.

Also, if the intended meaning is Let’s correct..., the usual first-person plural command would be:

• Rectifiquemos en la hoja de respuestas.

So Rectificamos is grammatically possible, but whether it sounds most natural depends on whether it is a statement, a past action, or an instruction.