A reunião era para começar às nove, mas eu cheguei tarde por causa do engarrafamento.

Because reunião is a countable noun, and in Portuguese it usually needs an article when you are talking about a specific event.

• A reunião = the meeting
• reunião by itself would sound incomplete here

So A reunião era para começar... means The meeting was supposed to start...

Also, reunião is a feminine noun, so it takes a, not o.

Era para começar means was supposed to start or was meant to start.

Literally, it is something like:

• era = was
• para começar = to start

But together, ser para + infinitive is a very common way to express expectation, plan, or obligation:

• Era para começar às nove. = It was supposed to start at nine.
• Era para ele vir. = He was supposed to come.

So this structure is very useful to learn.

Because era is the imperfect of ser, and here it refers to an expected plan or schedule in the background.

• era para começar = it was supposed to start
• foi para começar would not sound natural here

The imperfect often sets the scene or describes what the situation/plan was. In this sentence, the plan was that the meeting would begin at nine, but then something happened: eu cheguei tarde.

So the contrast is:

• background/expectation: A reunião era para começar às nove
• completed event: eu cheguei tarde

Às is a contraction of:

• a = at
• as = the

So:

• a + as = às

Portuguese often uses an article before clock times:

• à uma = at one
• às duas = at two
• às nove = at nine

The accent is important because às is not the same as as.

• as = the (feminine plural)
• às = to the / at the

Because the full idea is something like às nove horas = at nine hours.

Since hora is feminine, the article is feminine too:

• à uma (hora)
• às nove (horas)

Even when horas is not said, the feminine article remains.

Because cheguei tarde means I arrived late, which is the natural way to express this idea.

• cheguei = I arrived
• tarde = late

You would not say eu era tarde, because ser is not used that way in Portuguese.

If you want to say I was late, Portuguese often uses:

• cheguei tarde = I arrived late
• estava atrasado/a = I was late

In this sentence, cheguei tarde is the most natural choice because it focuses on the moment of arrival.

Cheguei is the preterite form of chegar. It is used because the speaker is describing a completed action:

• eu cheguei = I arrived

The sentence is about one specific event in the past. The speaker arrived late on that occasion, so the preterite is the right tense.

Compare:

• cheguei tarde = I arrived late
• chegava tarde = I used to arrive late / I was arriving late

The second one would suggest repetition or an ongoing background action, which is not the meaning here.

Yes. Portuguese often drops subject pronouns when the verb form already makes the subject clear.

So both are correct:

• mas eu cheguei tarde
• mas cheguei tarde

Since cheguei clearly means I arrived, eu is optional.

If eu is included, it can add a little emphasis or clarity. In speech, native speakers may include it or leave it out depending on style and context.

Both can relate to being late, but they are used differently.

• chegar tarde = to arrive late
• estar atrasado/a = to be late

So:

• eu cheguei tarde = I arrived late
• eu estava atrasado = I was late

In this sentence, the speaker is talking about the arrival itself, so cheguei tarde fits best.

Also remember that atrasado changes for gender if it describes a person:

• atrasado = masculine
• atrasada = feminine

But tarde does not change.

Por causa de means because of.

In this sentence:

• por causa do engarrafamento = because of the traffic jam

The do is a contraction:

• de + o = do

So the full structure is:

• por causa de + noun
• por causa do engarrafamento
• por causa da chuva
• por causa dos atrasos

This is a very common expression in everyday Portuguese.

Because engarrafamento is a masculine singular noun:

• o engarrafamento = the traffic jam

After por causa de, Portuguese contracts the preposition de with the article:

• de + o = do

So:

• por causa de o engarrafamento becomes por causa do engarrafamento

This kind of contraction is extremely common in Portuguese.

Here, engarrafamento means traffic jam.

It is a normal, widely understood word in European Portuguese. It refers to heavy traffic where cars are moving very slowly or not moving.

Examples:

• Houve um engarrafamento na autoestrada. = There was a traffic jam on the motorway.
• Apanhei um engarrafamento. = I got stuck in a traffic jam.

You may also hear people talk about trânsito depending on the context, but engarrafamento is a very standard word.

Yes, absolutely.

• por causa do trânsito = because of the traffic
• por causa do engarrafamento = because of the traffic jam

The second one is more specific: it suggests an actual jam or blockage. The first one is broader and can just mean traffic conditions in general.

So both are natural, but engarrafamento is a bit stronger and more precise here.

The sentence has two main parts joined by mas:

1. A reunião era para começar às nove

   • The meeting was supposed to start at nine

2. mas eu cheguei tarde por causa do engarrafamento

   • but I arrived late because of the traffic jam

So the pattern is:

• statement of expectation
  • mas
    • what actually happened

This is a very common and useful sentence pattern in Portuguese.

Yes, a little. Portuguese allows some flexibility, although the original version is very natural.

For example:

• A reunião era para começar às nove, mas cheguei tarde por causa do engarrafamento.
• Por causa do engarrafamento, cheguei tarde, mas a reunião era para começar às nove.

But the original order is the clearest and most neutral.

If you move por causa do engarrafamento to the front, you give more emphasis to the reason.

In informal speech, especially fast speech, you might hear:

• A reunião era para começar às nove, mas cheguei tarde por causa do engarrafamento.

This is already quite natural and conversational.

In very informal speech, some speakers may reduce para to pra in pronunciation or writing, but in standard European Portuguese writing, para is the safer form to use.

So for learners, the original sentence is a good standard model.