Dejamos el asunto pendiente hasta el lunes, porque ya era muy tarde.

Dejamos is the preterite, which presents the action as a completed event: we left / we put off / we left pending.

Here, the speaker is referring to a specific decision made at a particular moment in the past, so the preterite fits well.

Dejábamos would sound more like:

• an ongoing past action,
• a repeated habit,
• or background information.

So in this sentence, dejamos = we decided to leave the matter unresolved until Monday.

Era is the imperfect, and that tense is often used for:

• background description,
• states,
• time,
• age,
• weather,
• and general circumstances in the past.

In ya era muy tarde, the sentence is describing the situation at that time: it was already very late. That is background information explaining why they stopped.

If you used fue, it would sound more like it turned out to be or it became, which is not the usual idea here.

So the tense contrast is very natural:

• Dejamos = the completed action
• era muy tarde = the background reason or circumstance

The pattern dejar algo pendiente means:

• to leave something pending
• to leave something unresolved
• to postpone dealing with something

So dejamos el asunto pendiente means they did not finish dealing with the matter and left it for later.

This is a very common expression in Spanish. Similar examples:

• Dejé el trabajo pendiente para mañana.
• Vamos a dejar este tema pendiente.

Here pendiente works like a descriptive adjective that tells you the state of el asunto: the matter was left pending.

Spanish often places adjectives after the noun, especially when they describe a state or characteristic in a straightforward way.

So:

• el asunto pendiente = the pending matter / the unresolved matter

In this sentence, the structure is:

• dejamos
  • el asunto
    • pendiente

That means:

• we left the matter pending

It is similar to patterns like:

• dejar la puerta abierta = to leave the door open
• dejar la mesa limpia = to leave the table clean

In Spanish, articles are used more often than in English. El asunto means the matter / the issue, referring to a specific matter already known in the context.

Leaving out the article and saying dejamos asunto pendiente would sound unnatural in standard Spanish.

So el is there because Spanish normally wants a determiner before a countable singular noun in this kind of sentence.

Here hasta el lunes means until Monday.

It tells you the matter will remain unresolved up to Monday, when they will presumably return to it.

This is different from simply saying:

• el lunes = on Monday

So:

• Lo dejamos hasta el lunes = We left it until Monday / We postponed it until Monday
• Lo hacemos el lunes = We’ll do it on Monday

In real usage, hasta el lunes can sometimes imply both ideas together: it remains pending until then, and that is when it will be picked up again.

These are different forms:

• porque = because
• por qué = why

In your sentence, it gives the reason:

• porque ya era muy tarde = because it was already very late

So porque is the correct one.

Quick comparison:

• ¿Por qué lo dejamos pendiente? = Why did we leave it pending?
• Lo dejamos pendiente porque era tarde. = We left it pending because it was late.

Ya here means already.

So:

• era muy tarde = it was very late
• ya era muy tarde = it was already very late

It adds the idea that the time had advanced further than was convenient or expected. It strengthens the reason for stopping.

No, not in standard Spanish for telling time or describing that it was late.

Spanish normally uses ser for time-related expressions:

• Es tarde
• Era tarde
• Ya era muy tarde

Using estar here would sound wrong.

A useful rule:

• ser is used for time: Es la una, Es tarde
• estar is used for states or locations: Estoy cansado, Está en casa

Spanish often leaves out the subject pronoun because the verb ending already tells you who the subject is.

Dejamos can mean we leave or we left, depending on context, and the ending -amos shows the subject is nosotros.

So nosotros is unnecessary unless you want to:

• emphasize we,
• contrast with someone else,
• or avoid ambiguity.

Natural Spanish usually prefers:

• Dejamos el asunto pendiente...

rather than:

• Nosotros dejamos el asunto pendiente...

Formally, dejamos can be:

• present: we leave
• preterite: we left

The context tells you which one it is.

In this sentence, the rest of the wording clearly places it in the past:

• porque ya era muy tarde

Since era is past, the natural reading is:

• Dejamos = we left

So context resolves the ambiguity.

Yes. Asunto is a common and useful word for:

• matter,
• issue,
• affair,
• business.

Depending on context, Spanish could also use:

• tema = topic / issue
• cuestión = question / issue
• problema = problem

But el asunto sounds very natural here, especially when referring to something being discussed or dealt with.

Yes, if the speaker wants to be more explicit.

• hasta el lunes = until Monday
• hasta el próximo lunes = until next Monday

If the context already makes it clear which Monday is meant, hasta el lunes is enough and sounds very natural.

A broad Spain pronunciation would be roughly:

deh-HA-mos el ah-SOON-to pen-DYEN-te AS-ta el LOO-nes, por-KE ya EH-ra muy TAR-de

A few helpful notes:

• j in dejamos is a strong throaty sound, like the ch in Scottish loch
• h in hasta is silent
• ll in lunes does not appear here, but in most of Spain ll and y are pronounced alike
• z is not in this sentence, so there is no special Spain th sound to worry about here

Yes, often it can.

You may see both:

• Dejamos el asunto pendiente hasta el lunes porque ya era muy tarde.
• Dejamos el asunto pendiente hasta el lunes, porque ya era muy tarde.

The comma is not always necessary before porque when it introduces a straightforward reason. Some writers include it to mark a pause or make the sentence easier to read.

So with or without the comma, the meaning stays the same.