Learn Hardcore Chinese: jīntiān xiàbān yǐhòu wǒ xiǎng mǎshàng huíjiā. - After work today, I want to go home right away.

The subject 我 is understood for 下班 even though it appears later in the sentence. Chinese often does this: the subject logically controls the whole clause, even if the time phrase comes first.

What exactly does 下班 mean? I thought 班 meant “class”.

班 can mean “class” in the school sense, but it also means “work shift / duty period”.

上班 – to go to work / be on duty
下班 – to get off work / finish a shift
下课 – to finish a class (literally “class ends”)

So 下班 literally is “(to) come off shift”, and in everyday usage it simply means “to get off work”.

What is 以后 doing here? Is it like the English preposition “after”?

Yes, 以后 is functioning like “after” or “later (than that)”, but it behaves more like a postposition in Chinese.

Pattern:

[Verb / Event] + 以后
= after [doing that]

Examples:

下班以后 – after (I) get off work
吃饭以后 – after eating
毕业以后 – after graduating

So 今天下班以后 = after getting off work today.

You normally don’t need an extra preposition like “在” or “从” here; 以后 itself handles the “after” meaning.

Could I say 今天我下班以后想马上回家 instead? Does the position of 我 matter?

今天我下班以后想马上回家 is also grammatically correct and natural.

Compared forms:

今天下班以后我想马上回家。
今天我下班以后想马上回家。
我今天下班以后想马上回家。

All three are acceptable. The differences are subtle:

(1) and (3) are the most common.
(1) strongly groups 今天下班以后 as the time frame.
(3) feels more like normal Subject + time + rest of sentence word order.
(2) is fine but slightly less common; it visually splits 今天 and 下班以后.

For a learner, (1) and (3) are the best patterns to copy.

Why is 想 used here? What’s the difference between 想, 要, and 会 in a sentence like this?

These three express different nuances:

想 – want to / feel like / would like to (desire or intention, relatively soft)
要 – want to / going to / plan to (stronger intention or plan)
会 – will / be likely to (ability or prediction about the future)

In this sentence:

我想马上回家。
I want to go home right away / I’d like to go straight home.

If you say:

我今天下班以后要马上回家。
That sounds more like a firm plan or decision: “I’m going to go straight home after work today.”
我今天下班以后会马上回家。
That sounds like a prediction: “I will (will probably) go straight home after work today.”

So 想 fits well because it talks about what you want to do.

There’s no word for “will” or a future tense. How do we know this is about the future?

Chinese doesn’t have verb endings for tense like English. Instead, it relies on:

Time words: 今天, 明天, 以后, 下周
Context and modal verbs like 想, 要, 会

Here, 今天 (today), 下班以后 (after getting off work), and 想 (want to) all signal that the action 回家 is in the future relative to now.

So even without a word that literally means “will”, a native speaker automatically understands it as “I want to go home right away after work today.”

Where does 马上 go in the sentence? Could I say 我马上想回家 instead?

In the given sentence:

我想马上回家。

马上 modifies 回家 (to go home): “to go home immediately.”

If you say:

我马上想回家。

Then 马上 most naturally modifies 想 (to think / to want), and it sounds more like:

“I immediately (suddenly) felt like going home.”

So:

我想马上回家。 – I want to go home right away. (adverb modifies the going home)
我马上想回家。 – I immediately began to want to go home / I right away thought of going home.

In your original meaning (go home immediately after work), 我想马上回家 is the natural choice.

Does 马上 mean “immediately after work” or “immediately after the moment of speaking”?

In this sentence the timeline is:

You finish work (下班以后).
Immediately after that, you go home (马上回家).

So 马上 is tied to 回家, and both are within the time frame “after getting off work today”.

You are speaking now about what you want to do later: once the 下班以后 condition is met, you will 马上回家.

Why is it just 回家 and not 回到家 or 回家去?

All of these are possible, but they have slightly different flavors:

回家 – go (back) home / return home.
Very common and neutral.
回到家 – return to home (emphasizes reaching the destination).
Example: 回到家以后，我就睡觉。 – After getting back home, I go straight to bed.
回家去 – go back home (often with a sense of direction away from where you are now).
More explicit about “going away (to home)”.

In most everyday speech, 回家 is the default and completely natural. In 今天下班以后我想马上回家, 回家 is exactly what a native would say.

Can the subject 我 be omitted, like 今天下班以后想马上回家?

Yes, in context it can be omitted:

今天下班以后想马上回家。

If it’s already clear from the conversation that you are the subject, this is natural and sounds a bit more casual or diary-like.

Chinese often drops pronouns when they are obvious from context. However, in an isolated sentence (like in a textbook or exercise), including 我 is more standard and clearer:

今天下班以后我想马上回家。

Could I use 之后 instead of 以后? What’s the difference between 以后 and 之后 here?

In this sentence, 以后 and 之后 are effectively interchangeable:

今天下班以后我想马上回家。
今天下班之后我想马上回家。

Both mean “After work today, I want to go straight home.”

Subtle differences (not big in this context):

以后 is very common in spoken Chinese and can also mean “in the (long-term) future”:
以后我想住在北京。 – In the future I want to live in Beijing.
之后 is a bit more formal and is often used to describe sequence in narration:
他吃完饭之后就出门了。

For your sentence, 以后 is slightly more colloquial, but both are fine.

Why doesn’t 今天 need a measure word or classifier?

Words like 今天 (today), 明天 (tomorrow), 昨天 (yesterday), 现在 (now) are time words, and they are already complete nouns of time. You don’t need to say anything like:

✗ 一个今天
✗ 在今天的时候 (for ordinary conversation, this is overcomplicated)

Just 今天 is enough. It directly functions as a time expression at the beginning of the sentence:

今天下班以后我想马上回家。
After work today, I want to go straight home.