El otro día empezó la reparación.

It is a very common time expression meaning the other day or a few days ago.

Even though it is made up of normal words:

• el = the
• otro = other
• día = day

together el otro día works as a fixed expression referring to a recent day in the past, not literally the other day in a contrastive sense.

Because el otro día is the standard full expression.

In English, learners may want to think only about other day, but in Spanish the article is part of the phrase:

• el otro día

This is similar to how Spanish often uses articles in places where English does not.

Empezó is the third-person singular preterite of empezar.

So it means:

• he/she/it started
• you started (formal singular, usted)

In this sentence, it matches la reparación, which is singular:

• La reparación empezó
• The repair started

The preterite is used because this sentence refers to a completed event at a specific time in the past: the starting of the repair.

The idea is:

• at some point the other day, the repair began

Spanish uses the preterite for events seen as complete and bounded:

• empezó = it started

If you used the imperfect, empezaba, it would suggest background, repetition, or an action in progress, which does not fit as naturally here.

The accent mark shows the stress falls on the last syllable:

• em-pe-zó

It is also part of the correct written form of this preterite tense.

This is important because Spanish spelling uses accent marks very systematically. In verbs, they often help distinguish forms clearly:

• empiezo = I start
• empezó = he/she/it started

It is the subject.

A very common English-speaker reaction is to assume that because it comes after the verb, it must be the object. But in Spanish, subjects can come after the verb.

Here:

• empezó = started
• la reparación = the repair

So the structure is basically:

• The repair started the other day

You can tell la reparación is the subject because the verb is in the third-person singular, agreeing with that singular noun.

Because Spanish word order is more flexible than English word order.

All of these are possible:

• El otro día empezó la reparación.
• La reparación empezó el otro día.
• Empezó la reparación el otro día.

The original version sounds natural because Spanish often places:

1. a time expression first, and then
2. the verb before the subject

This can make the sentence sound smooth and narrative, especially when introducing an event.

Spanish usually needs an article with a countable noun when you are talking about a specific thing.

So:

• la reparación = the repair / the repair work

Without the article, the sentence would sound incomplete or unnatural in normal usage.

The article suggests that this is a specific repair already known from context, such as a repair to a building, machine, road, etc.

Because día is a masculine singular noun:

• el día

Adjectives must agree with the noun they describe, so:

• el otro día

If the noun were feminine, you would use otra:

• la otra semana = the other week

Yes. Comenzó and empezó are very close in meaning here.

So you could also say:

• El otro día comenzó la reparación.

Both are correct. Very generally:

• empezar is extremely common and neutral
• comenzar can sound a little more formal in some contexts

But in this sentence, either one works.

It can mean either, depending on context.

In a sentence like this, la reparación often refers to the repair work or the repair process beginning:

• road repairs
• building repairs
• machine repairs

So a natural English understanding is often:

• The repair work started the other day.

That is why the sentence sounds normal even though, literally, the repair is what started.

Yes, but it changes the feel.

• Empezó la reparación = The repair started
• Se empezó la reparación = The repair was started / They started the repair

The version with se is more impersonal and can sound more administrative or formal. The original sentence is simpler and more direct.