Enterramos la caja ayer.

Because enterramos can be either:

• present: we bury
• preterite: we buried

In this sentence, ayer (yesterday) makes it clear that it refers to a completed action in the past, so the correct reading is we buried.

So:

• Enterramos la caja. = could mean We bury the box or We buried the box
• Enterramos la caja ayer. = clearly We buried the box yesterday

Spanish often leaves out subject pronouns when they are not needed. The verb ending already tells you who the subject is.

• enterramos = we bury / we buried

So nosotros enterramos la caja ayer is possible, but usually unnecessary unless you want emphasis or contrast.

For example:

• Enterramos la caja ayer. = neutral
• Nosotros enterramos la caja ayer. = We buried the box yesterday (not someone else)

La caja is the direct object. It is the thing that receives the action of the verb.

• Enterramos = we buried
• la caja = the box

So the action is being done to the box.

Because Spanish often uses the definite article where English uses the.

• la caja = the box

If you said una caja, that would mean a box.

So:

• Enterramos la caja ayer. = We buried the box yesterday.
• Enterramos una caja ayer. = We buried a box yesterday.

Because la caja is a thing, not a specific person.

In Spanish, the personal a is usually used before a specific human direct object.

Compare:

• Enterramos la caja. = We buried the box.
• Vimos a María. = We saw María.

You do not use the personal a with ordinary objects like la caja.

Yes, Spanish word order is flexible. Ayer can often go in different places without changing the basic meaning.

These are all possible:

• Enterramos la caja ayer.
• Ayer enterramos la caja.
• La caja la enterramos ayer. (more marked, with emphasis on the box)

The version with ayer at the end sounds natural and neutral.

It is the preterite in this sentence.

The Spanish preterite is used for a completed action in the past. Since burying the box happened yesterday, it is treated as a finished event.

Verb breakdown:

• infinitive: enterrar = to bury
• preterite, nosotros form: enterramos = we buried

Yes, enterrar is regular in the preterite, but it has a stem change in some present-tense forms.

Infinitive

• enterrar = to bury

Preterite

• yo enterré
• tú enterraste
• él/ella enterró
• nosotros enterramos
• vosotros enterrasteis
• ellos enterraron

Present

• yo entierro
• tú entierras
• él/ella entierra
• nosotros enterramos
• vosotros enterráis
• ellos entierran

Notice that in the present tense, many forms change from e to ie (entierro, entierras...), but nosotros does not change: enterramos.

That is one reason enterramos can look tricky: it is the same in the present nosotros and the preterite nosotros.

A Spain Spanish pronunciation would be approximately:

en-te-RRA-mos

A few key points:

• The rr is a strong rolled sound.
• The stress is on ra: enterRÁmos
• The e and a are clear, short vowels.

So enterramos sounds different from a word with a single r.

Because the verb is enterrar, which is spelled with rr in the infinitive and throughout forms where that sound stays between vowels.

In Spanish spelling:

• r between vowels usually sounds softer
• rr between vowels marks the strong rolled r sound

So enterramos keeps that strong sound and the spelling rr.

Not with the same meaning.

The sentence uses the preterite because it describes a completed event: we buried the box yesterday.

If you used the imperfect, you would normally be describing an ongoing, repeated, or background action, which does not fit as naturally with ayer in this context.

• Enterramos la caja ayer. = We buried the box yesterday.
• Enterrábamos la caja... = We were burying the box... / We used to bury the box...

So the preterite is the normal choice here.

Yes, but the emphasis changes.

• Enterramos la caja ayer. = neutral statement
• La caja la enterramos ayer. = emphasizes the box

In the second version, Spanish often repeats the object with la before the verb. That structure is more marked and usually used when you are contrasting or highlighting the object.

Yes, it is completely natural in Spain Spanish.

Nothing in the sentence is specifically non-Spain or strongly regional. A speaker in Spain would understand and use it normally.

If you added the subject pronoun nosotros, that would still be correct, but the version without it is more typical unless you want emphasis.