El incidente sucedió ayer.

Because the sentence refers to a completed event in the past, so Spanish uses the preterite here.

• sucedió = it happened
• sucede = it happens / is happening
• sucedía = it was happening / used to happen

Since ayer tells you the incident took place at a specific finished time, sucedió is the most natural choice.

Sucedió is the third-person singular preterite of suceder.

So it means:

• he/she/it happened
• he/she/it occurred

In this sentence, the subject is el incidente, so the verb is singular:

• El incidente sucedió ayer.

The accent mark shows where the stress goes: su-ce-DIÓ.

Without the accent, Spanish pronunciation rules would suggest a different stress pattern. The written accent tells you clearly that the last syllable is stressed.

This is very common in preterite forms like:

• habló
• comió
• vivió
• sucedió

In most of Spain, the c before e is pronounced like the th in thin.

So sucedió is approximately:

• soo-the-DYOH in most of Spain

And incidente is approximately:

• een-thee-DEN-teh

In much of Latin America, those c sounds would be pronounced like s instead.

Yes, incidente is a masculine noun, so it takes el.

This is something learners often ask because the word ends in -e, not -o. Nouns ending in -e can be either masculine or feminine, so you usually have to learn the gender with the noun:

• el incidente
• el problema
• la clase
• la noche

So here, el is simply the correct article for this noun.

Yes. All three are possible, but they are not always identical in style.

• sucedió = happened / occurred
• ocurrió = occurred; often a bit more formal or neutral
• pasó = happened; very common in everyday speech

So these all work:

• El incidente sucedió ayer.
• El incidente ocurrió ayer.
• El incidente pasó ayer.

In many everyday situations, pasó is the most conversational option.

Yes, but it is slightly less common in casual speech than pasar when talking about events.

For example, Spanish speakers very often say:

• ¿Qué pasó? = What happened?

More formal or written language may prefer:

• ¿Qué sucedió?
• ¿Qué ocurrió?

So suceder is perfectly normal, but it can sound a little more formal or narrative depending on context.

Yes, ayer can move.

The original sentence is completely natural:

• El incidente sucedió ayer.

But you can also say:

• Ayer sucedió el incidente.
• Ayer el incidente sucedió. (possible, but less natural in many contexts)

Putting ayer at the end is a very common neutral word order. Spanish is more flexible than English, but not every possible order sounds equally natural.

No. Ayer is used by itself.

• El incidente sucedió ayer.

Not:

• en ayer
• a ayer

This is like English yesterday, which also does not need a preposition in a sentence like It happened yesterday.

Not in this sentence.

Because incidente is the subject noun and refers to a specific incident, Spanish needs the article:

• El incidente sucedió ayer.

If you said only:

• Incidente sucedió ayer

that would sound incorrect in normal Spanish.

Not exactly.

Incidente usually means incident, not necessarily an accident. It can be any event, especially one that is notable, unpleasant, or unusual.

If you specifically mean accident, Spanish often uses:

• accidente

So:

• el incidente = the incident
• el accidente = the accident

They are related ideas, but not the same word.

The verb subject pronoun can be dropped in Spanish, but here the subject is not a pronoun; it is the noun phrase el incidente.

So you would not normally drop it unless the context already made the subject clear and you rephrased the sentence.

For example:

• Sucedió ayer. = It happened yesterday.

That works if everyone already knows what it refers to.

But if you want to say explicitly the incident, then you keep:

• El incidente sucedió ayer.

It is grammatical and natural, especially in writing, news, reports, or storytelling.

In everyday spoken Spanish in Spain, many people might more often say:

• El incidente pasó ayer.
• Eso pasó ayer.
• Ocurrió ayer.

So El incidente sucedió ayer is absolutely correct, but depending on tone and context, another verb may sound more everyday and conversational.