Learn Hardcore Chinese: míngtiān zǎoshang wǒmen zài jiàoshì shàngkè. - Tomorrow morning we have class in the classroom.

Putting 明天早上 in the middle, as in 我们在教室明天早上上课, sounds unnatural or wrong. Time expressions normally go near the beginning of the sentence, before the subject or right after it:

明天早上我们在教室上课。
我们明天早上在教室上课。 (also OK)

But not between the place and the verb.

Why do we say 明天早上 and not 早上明天 for “tomorrow morning”?

Chinese puts time words in a big → small order:

明天 = tomorrow (bigger unit: the whole day)
早上 = morning (smaller part of the day)

So you say:

明天早上 (tomorrow-morning)

Other examples:

下个星期一早上 (next–week–Monday–morning)
去年冬天 (last year’s winter)

早上明天 breaks this large-to-small pattern and is not used.

There is no word like “will” in the sentence. How does Chinese show it’s about the future?

Chinese usually does not need a separate word for “will”. The time word itself makes the future meaning clear:

明天早上我们在教室上课。
→ Because of 明天早上, it’s clearly future: We will have class…

You can add words like:

会 (huì) – will / be likely to
要 (yào) – be going to / plan to

But they are optional and add extra nuance:

明天早上我们会在教室上课。 (emphasizes it will happen)
明天早上我们要在教室上课。 (sounds more like an arrangement / plan / obligation)

The plain sentence without 会/要 is already a natural way to talk about the future.

What exactly is 在 doing here? Is it a verb “to be at” or a preposition “at, in”?

In 我们在教室上课, 在 works like a preposition introducing the location:

在教室 = in the classroom / at the classroom

The pattern is:

Subject + 在 + Place + Action
我们在教室上课。
We at (the) classroom have class.

You can think of 在 here as similar to English “at” or “in” before an activity:

We have class *in the classroom.*
They study *at home.* → 他们在家学习。

Can we drop 在 and just say 我们教室上课?

No, not in standard Mandarin. You normally need 在 before a place word when that place is giving the location of an action:

✔ 我们在教室上课。
✘ 我们教室上课。 (ungrammatical)

Without 在, 教室 would sound like a direct object (like “we classroom something”), which doesn’t make sense here. So keep:

在教室 (at/in the classroom)

What does 上课 literally mean? Is 上 the verb and 课 the object?

Yes. Literally:

上 (shàng) = to go up / to attend / to go to (class, work, etc.)
课 (kè) = class, lesson

Together 上课 is often treated as a set verb phrase meaning:

to have class
to go to class
to attend class
to hold class (for a teacher)

Examples:

我八点上课。 – I have class at 8.
老师在教室上课。 – The teacher is teaching in the classroom.
学生在教室上课。 – The students are in class / having class in the classroom.

So you can think of 上课 as one unit: “have class / be in class.”

Why doesn’t Chinese use a word for “the” before 教室? Why not “the classroom”?

Chinese has no articles like “a / an / the”. A bare noun can mean:

“a classroom”
“the classroom”
“classrooms” (in general)

Context fills in the specific meaning. In this sentence:

在教室上课
→ have class in the classroom (the one both speaker and listener understand)

If you need to be specific, you add other words:

在那个教室上课 – in that classroom
在二号教室上课 – in Classroom 2
在这间教室上课 – in this classroom

What’s the difference between 早上, 上午, and 早晨?

All are related to “morning”, but with slightly different usage:

早上 (zǎoshang)
- Everyday, very common.
- Roughly: from getting up until around 9–10 a.m.
- 明天早上 – tomorrow morning (very natural)
上午 (shàngwǔ)
- More formal / neutral; often used in schedules, official contexts.
- Roughly: 8 a.m. to noon.
- 明天上午开会。 – We have a meeting tomorrow morning / forenoon.
早晨 (zǎochén)
- More literary or descriptive, often for early morning, sometimes poetic.
- 清早晨 – early in the morning.

In your sentence, 明天早上 is the most natural everyday choice.

Is 早上 pronounced zǎoshàng (3rd + 4th tone) or is the second syllable neutral?

You will see both in different descriptions, but in everyday speech:

早上 is most often zǎoshang:
- 早 – 3rd tone
- 上 – neutral tone (sometimes written as a 5th tone)

So: zǎo·shang (with the second syllable light and unstressed).

Some dictionaries may list zǎoshàng (3rd + 4th), but in natural spoken Mandarin, the neutral-tone version is more common.

If I want to say “We HAD class in the classroom this morning”, where would 了 go?

You’d typically put 了 after 上 (the verb) to show the action is completed:

今天早上我们在教室上了课。
This morning we had class in the classroom.

Structure:

今天早上 – this morning
我们 – we
在教室 – in the classroom
上了课 – had (attended) class (completed)

You don’t say: ✘ 在教室了上课.

Can I say 明天早上我们有课 instead of 明天早上我们在教室上课? What’s the difference?

Yes, you can, but there is a nuance:

明天早上我们有课。
- Literally: “Tomorrow morning we have class (there is class).”
- Focus: the existence of class in your schedule.
- No location mentioned.
明天早上我们在教室上课。
- Focus: what you will be doing and where.
- Explicitly says it happens in the classroom.

So:

Use 有课 when talking about your timetable: whether you’re free or busy.
Use 在教室上课 when emphasizing location or the activity taking place where someone is.

Do I need a measure word with 教室 here, like 一个教室?

Not in this sentence. You only need a measure word when you:

Specify number:
- 一个教室 – one classroom
- 三个教室 – three classrooms
Or emphasize a specific individual room with a classifier like 间:
- 一间教室

Here, 教室 just names the place where the action happens, so no measure word is needed:

在教室上课 – have class in the classroom.