hěn bàoqiàn, míngtiān wǒ bù néng lái shàngkè.

In this sentence, 很抱歉 is the standard way to say sorry or I’m very sorry.

A useful thing to know is that in Mandarin, adjectives often need something before them when they function like the main predicate of a sentence. So 很 is very commonly placed before adjectives, and it does not always sound as strong as English very.

So:

• 抱歉 = sorry; regretful
• 很抱歉 = sorry / very sorry

In real usage, 很抱歉 is a natural fixed expression.

Yes, you can. 抱歉 by itself is possible, especially in short expressions, signs, messages, or formal contexts.

For example:

• 抱歉，我来晚了。 = Sorry, I came late.

But in full sentences, 很抱歉 often sounds smoother and more natural. It is a very common polite expression.

Mandarin often places time expressions early in the sentence, usually before the subject or right after it.

So these are both possible patterns:

• 明天我不能来上课。
• 我明天不能来上课。

Both mean the same thing: Tomorrow I can’t come to class.

The version in your sentence puts the time first, which is very common in Mandarin.

不能 means cannot / am not able to / am not allowed to.

With modal verbs like 能, Mandarin usually uses 不, not 没.

• 不 能 = cannot / won’t be able to
• 没能 also exists, but it is different: it usually refers to did not succeed in being able to in a past situation.

So in this sentence:

• 我不能来上课 = I can’t come to class.

That is the normal way to say it.

Here 能 most naturally means be able to.

So 我不能来上课 means:

• I can’t come to class.
• I’m unable to come to class.

Depending on context, 能 can also involve permission or possibility, but in this sentence it is usually understood as practical ability or availability.

This is a very common learner question.

Mandarin chooses 来 or 去 based on the speaker’s point of view.

• 来 = come, toward the speaker or the relevant place
• 去 = go, away from the speaker

In a sentence like this, 来上课 is often used when talking to the teacher, school, or class group, so the class is treated as the relevant location. It feels like come to class.

If the speaker is talking from a different perspective, 去上课 may also be possible.

So:

• 不能来上课 = can’t come to class
• 不能去上课 = can’t go to class

Both can be correct, but 来上课 fits very naturally when addressing the class or teacher.

Yes, 上课 is a common verb-object expression meaning attend class / have class / go to class / start class, depending on context.

Literally:

• 上 = go up / attend / begin in some expressions
• 课 = class / lesson

Together, 上课 means something like attend class or be in class.

Examples:

• 我去上课。 = I’m going to class.
• 老师在上课。 = The teacher is teaching class.
• 我们八点上课。 = We start class at eight.

Mandarin often does not use separate words in the same way English does.

In English, we say:

• come to class

In Mandarin, the idea is expressed directly with the verb phrase:

• 来上课

So you do not need an extra word corresponding to English to here.

Yes. That is also perfectly natural.

Compare:

• 很抱歉，明天我不能来上课。
• 很抱歉，我明天不能来上课。

Both are correct. The difference is mainly emphasis and rhythm:

• 明天我... highlights the time earlier.
• 我明天... introduces the subject first, then the time.

Mandarin is flexible with time placement, as long as the sentence stays clear.

很抱歉 is polite and slightly formal, but still very common in everyday use.

Compared with some other expressions:

• 对不起 = sorry; excuse me; stronger and very common
• 不好意思 = sorry / excuse me / feel embarrassed; often softer and more casual
• 很抱歉 = I’m very sorry; somewhat polite and often a little more formal

So this sentence sounds polite and appropriate, especially when informing a teacher.

Sometimes yes, if the context is completely clear.

For example, in a text message to a teacher, someone might write:

• 很抱歉，明天不能来上课。

That is natural because the speaker is obviously talking about themselves.

But including 我 makes the sentence clearer and is especially helpful for learners.

The comma after 很抱歉 helps separate the apology from the reason or main message.

• 很抱歉，明天我不能来上课。

It is similar to saying:

• Sorry, I can’t come to class tomorrow.

In writing, the comma makes the sentence easier to read. In speech, it reflects a natural pause.

Yes. 不 normally has fourth tone: bù.

But when 不 comes before another fourth-tone syllable, it usually changes to second tone in pronunciation.

Since 能 is second tone, not fourth tone, there is no tone change here.

So you pronounce it:

• bù néng

By contrast:

• 不是 is pronounced bú shì because 是 is fourth tone.

A natural rhythm is:

Hěn bàoqiàn, míngtiān wǒ bù néng lái shàngkè.

Helpful points:

• 很 = 3rd tone
• 抱 = 4th tone
• 歉 = 4th tone
• 明 = 2nd tone
• 天 = neutral/high level in this word as part of míngtiān
• 我 = 3rd tone
• 不 = 4th tone here
• 能 = 2nd tone
• 来 = 2nd tone
• 上 = 4th tone
• 课 = 4th tone

There is a small pause after 很抱歉.

Yes, you can say:

• 对不起，明天我不能来上课。

That is also correct and natural.

The difference is mostly nuance:

• 对不起 is very common and direct.
• 很抱歉 sounds a bit more formal or careful.

If you are messaging a teacher, both work, but 很抱歉 can sound especially polite.

The sentence is complete without a reason.

• 很抱歉，明天我不能来上课。

This already clearly communicates the apology and the fact that the speaker cannot attend class tomorrow.

If you want, you can add a reason after it, for example:

• 很抱歉，明天我不能来上课，因为我生病了。 = I’m sorry, I can’t come to class tomorrow because I’m sick.

But a reason is optional.