Я заранее предупредила коллегу, что на совещание могу опоздать.

Предупредила is the past tense, feminine singular form of предупредить.

That tells you the speaker is:

• female
• talking about a completed action in the past

So:

• я предупредил = I warned / informed beforehand (said by a man)
• я предупредила = I warned / informed beforehand (said by a woman)

Russian past tense agrees with gender in the singular.

The verb предупредить is perfective, and here it fits because the sentence refers to one completed act of warning/informing.

The idea is:

• I did warn my colleague
• that action is viewed as finished

If you used the imperfective предупреждала, it would sound more like:

• I was warning
• I used to warn
• I had been warning

In this sentence, the speaker means a single completed action, so предупредила is the natural choice.

Заранее means in advance, beforehand.

It modifies предупредила, so the idea is:

• Я заранее предупредила коллегу = I warned my colleague beforehand

It usually goes before the verb, as it does here, but Russian word order is flexible:

• Я заранее предупредила коллегу
• Я предупредила коллегу заранее

Both are possible, though the first is very natural and common.

Because предупредить normally takes a direct object in the accusative case: you warn someone.

So:

• предупредить кого? → коллегу

That is why you get the accusative singular form коллегу.

Compare:

• Я предупредила коллегу = I warned my colleague

If you used коллеге, that would be dative, which does not work with this verb in this meaning.

Because что introduces a subordinate clause.

The structure is:

• Я заранее предупредила коллегу,
• что на совещание могу опоздать

In English, this is like:

• I warned my colleague that I might be late for the meeting.

Russian normally places a comma before что when it introduces this kind of clause.

Что means that and introduces the content of what was said, warned, explained, known, etc.

Here it introduces what the speaker warned the colleague about:

• что на совещание могу опоздать = that I might be late for the meeting

It is a very common pattern:

• сказал, что... = said that...
• объяснила, что... = explained that...
• предупредила, что... = warned that...

This is a very common question.

Here опоздать на takes the accusative:

• опоздать на урок
• опоздать на поезд
• опоздать на встречу
• опоздать на совещание

So на совещание means to the meeting in the sense of arriving late for it.

Compare:

• на совещание = to the meeting / for the meeting
• на совещании = at the meeting

Examples:

• Я опоздал на совещание = I was late for the meeting
• Я был на совещании = I was at the meeting

Yes, могу literally means I can, but in Russian it is often used to express possibility, not just ability.

So могу опоздать can mean:

• I may be late
• I might be late
• I could be late

It does not necessarily mean physical ability. Here it means there is a possibility that the speaker will arrive late.

In Russian, the present tense form of мочь is often used with an infinitive to talk about a future possibility.

So:

• могу опоздать literally looks like can be late
• but in context it means might be late in the upcoming situation

This is very natural Russian.

A similar pattern:

• Завтра я могу не прийти = Tomorrow I might not come

So the present tense of мочь often works like English may/might for future situations.

Опоздать is perfective because it refers to one completed instance of being late: arriving late for this particular meeting.

The sentence is about a single event:

• one meeting
• one possible late arrival

That is why опоздать fits well.

Compare:

• опоздать = to be late once / to arrive late
• опаздывать = to be late repeatedly / habitually / in an ongoing sense

Examples:

• Я могу опоздать на совещание = I might be late for the meeting
• Я часто опаздываю на совещания = I am often late for meetings

Yes, it often could be omitted:

• Заранее предупредила коллегу, что на совещание могу опоздать.

Russian often drops subject pronouns when they are clear from the verb form or context.

But keeping Я is also perfectly natural. It can sound:

• neutral
• slightly clearer
• a bit more explicit

So both are possible, depending on style and context.

No, Russian word order is flexible, but the original sentence is very natural.

The given order:

• Я заранее предупредила коллегу, что на совещание могу опоздать.

works well as a neutral sentence.

You could also hear variants such as:

• Я предупредила коллегу заранее, что на совещание могу опоздать.
• Коллегу я заранее предупредила, что на совещание могу опоздать.

But changing the order can shift emphasis. For a learner, the original version is a very good standard model.

Yes, but the meaning changes slightly.

• сказала коллеге = told my colleague
• предупредила коллегу = warned / let my colleague know in advance

Предупредила is more specific. It suggests:

• the speaker informed the colleague ahead of time
• so the colleague would know and not be surprised

So предупредила is better if the idea is I gave advance notice rather than simply I said.

A useful pattern here is:

[subject] + заранее + предупредить + кого, что...

So:

• Я заранее предупредила коллегу, что...

This means:

• I warned / informed my colleague in advance that...

Inside the second clause, you have:

мочь + infinitive

So:

• могу опоздать = might be late

Together, the sentence is built like this:

• I informed my colleague beforehand
• that I might be late for the meeting