Compramos la bebida ayer.

Here, compramos is the preterite (also called the simple past) of comprar.

So in this sentence, it means we bought.

Spanish often uses the preterite for a completed action in the past, and ayer makes that very clear.

Spanish often drops subject pronouns when they are not needed.

So instead of saying Nosotros compramos la bebida ayer, it is very normal to say simply Compramos la bebida ayer.

The ending -amos already tells you the subject is we.

Adding nosotros is possible, but it usually adds emphasis, contrast, or clarity.

This is a very common question because compramos can mean either:

• we buy (present)
• we bought (preterite)

They are spelled the same.

In this sentence, ayer means yesterday, so it forces a past-time interpretation. Because of that, compramos here must mean we bought.

Without a time word or more context, the form by itself could be ambiguous.

Comprar is a regular -ar verb.

In the preterite, the endings for regular -ar verbs are:

• yo compré
• tú compraste
• él/ella/usted compró
• nosotros/nosotras compramos
• vosotros/vosotras comprasteis
• ellos/ellas/ustedes compraron

So compramos is the nosotros form.

Interestingly, that same form is also used for the present tense nosotros form:

• compramos = we buy
• compramos = we bought

Context tells you which one it is.

La bebida means the drink or the beverage, so it refers to a specific drink that the speaker and listener can identify.

If you said una bebida, it would mean a drink, which sounds less specific.

Compare:

• Compramos la bebida ayer = we bought the drink
• Compramos una bebida ayer = we bought a drink yesterday

So the definite article la is used because the sentence is talking about a particular drink.

In Spanish, singular countable nouns usually need an article or another determiner.

So bebida by itself would usually sound incomplete in a sentence like this.

That is why Spanish normally says:

• la bebida
• una bebida
• esa bebida
• mi bebida

not just bare bebida in this kind of statement.

It is correct, but whether it sounds most natural depends on the situation.

Bebida is a general word meaning drink or beverage. It is perfectly fine, but in everyday conversation Spanish speakers might often be more specific, such as:

• el refresco = the soft drink
• el agua = the water
• el vino = the wine
• la cerveza = the beer

So la bebida is grammatical and understandable, but sometimes it can sound a bit general, depending on context.

Spanish word order is flexible, and ayer can go in different places.

Compramos la bebida ayer is completely natural.

You could also say:

• Ayer compramos la bebida
• Compramos ayer la bebida (less common in neutral everyday speech, but possible)

Putting ayer at the end is a very normal way to add the time information after the main statement.

Yes, absolutely.

Both of these are correct:

• Compramos la bebida ayer
• Ayer compramos la bebida

The difference is mostly one of focus or rhythm.

• Ayer compramos la bebida emphasizes when
• Compramos la bebida ayer sounds slightly more neutral in many contexts

Both are standard.

Because this form simply does not take one.

In the preterite, some forms do have written accents:

• compré
• compró

But compramos does not.

That means:

• compramos = we buy
• compramos = we bought

The spelling is the same in both tenses, and context tells you which meaning is intended.

Yes, that is grammatically correct.

But in Spanish, subject pronouns are often omitted unless there is a reason to include them.

Using nosotros may sound:

• emphatic
• contrastive
• clarifying

For example:

• Ellos no la compraron; nosotros compramos la bebida ayer.

So the version without nosotros is usually the most natural unless you want emphasis.

Good question. In Spain, the present perfect (hemos comprado) is often used for recent past actions connected to the present, especially with time expressions like hoy.

But with ayer, the simple past compramos is the normal choice:

• Compramos la bebida ayer.

Using hemos comprado ayer is generally not standard in careful Spanish.

So with ayer, learners should usually choose the preterite:

• ayer + preterite

Yes. You simply say ayer, not en ayer or anything similar.

So:

• ayer = yesterday
• hoy = today
• mañana = tomorrow

Examples:

• Llegó ayer.
• Trabajamos hoy.
• Salimos mañana.

This is different from English, where time expressions sometimes need prepositions in other contexts. In Spanish, ayer stands alone.