Learn Hardcore Chinese: xiàbān yǐhòu qǐng bǎ diànnǎo guāndiào. - After work, please turn off the computer.

It’s specifically about leaving work or the end of a work shift, not just “finish any task.” For finishing some piece of work/homework, you wouldn’t use 下班; you might use 做完 / 完成 instead.

Also, 下班 is used for working hours, while 下课 is used for classes (end of class/lesson).

How should I understand 下班以后? Is 以后 like “afterwards” or “later”?

以后 means “after” (in a time sense) or “in the future / later,” depending on context.

In 下班以后, it means “after getting off work.”
More generally: [event] + 以后 = “after [event].”

Examples:

吃饭以后去散步。 = “After eating, (we’ll) go for a walk.”
毕业以后他去了北京。 = “After graduating, he went to Beijing.”

So 下班以后 is a time phrase = “after (you) get off work.”

Can 下班以后 go somewhere else in the sentence, like at the end?

Yes, Chinese time phrases are flexible, but some positions are more natural.

All of these are acceptable:

下班以后，请把电脑关掉。
请你下班以后把电脑关掉。
请把电脑在下班以后关掉。 (grammatical but sounds a bit stiff/formal)

Most natural in everyday speech would be 1 or 2, where the time phrase 下班以后 comes near the beginning or just after the subject. Putting 在下班以后 after 把 is possible but less common in casual speech.

Why is there no explicit subject like “you” in the sentence? How do we know it’s an instruction to “you”?

Chinese often omits the subject when it’s obvious from context.

Here, it’s clearly an instruction, so the implied subject is “you”:

(你) 下班以后请把电脑关掉。
= “(You) please turn off the computer after work.”

In English we must say “you,” but in Chinese, commands or requests can usually drop 你 if it’s obvious who’s being addressed.

You can add it if you want to be explicit or slightly more personal:

你下班以后请把电脑关掉。
请你下班以后把电脑关掉。

What exactly does 请 do here? Is it necessary, and how polite is it?

请 is “please” and softens the sentence into a polite request rather than a bare command.

下班以后把电脑关掉。
= “Turn off the computer after work.” (can sound like an order)
下班以后请把电脑关掉。
= “Please turn off the computer after work.” (more polite / formal)

Politeness level:

With 请 alone: neutral-polite.
With 请你/麻烦你: a bit warmer/more explicitly polite.
- 下班以后麻烦你把电脑关掉。 = “Could I trouble you to turn off the computer after work?”

What is the function of 把 in this sentence, and why is it needed?

把 marks a “disposal structure”: it highlights what happens to the object.

Structure: [Subject] + 把 + [object] + [resulting action]

In the sentence:

请 (你) = subject
把电脑 = “(take) the computer”
关掉 = “turn off (completely)”

So 请把电脑关掉 emphasizes what you do to the computer (you cause it to be turned off).

Could you drop 把?

请关掉电脑。 is also correct and common.
请把电脑关掉。 feels a bit more specific/complete and is a very typical pattern, especially when there is a clear result (关掉, 吃完, 打开, etc.).

What’s the word order with 把? Where does everything go?

The basic 把 pattern is:

(Subject) + 把 + Object + Verb (+ Result / Complement)

In this sentence:

(你) = (implied subject)
把 = disposal marker
电脑 = object
关掉 = verb + result (turn off completely)

Plus the time phrase:

下班以后 usually goes before the 把-phrase:
- 下班以后，请把电脑关掉。
- 请你下班以后把电脑关掉。

What is the difference between 关 and 关掉 here?

Both relate to “turn off / close,” but 关掉 emphasizes completion (“switch off completely”).

关 = to turn off / close (more general)
掉 = a complement meaning “away/off, to completion”

So:

关电脑 = turn off the computer
关掉电脑 = turn the computer completely off (result is emphasized)
把电脑关掉 ≈ “turn the computer off (and it ends up off).”

In many situations, 关 alone is fine, and you’ll hear both:

下班以后请关电脑。
下班以后请把电脑关掉。

Is 关掉 a separable verb? Why can the object go between 关 and 掉 in some sentences but not in others?

Yes, 关掉 is a verb + result complement: 关 (to close/turn off) + 掉 (off/completely).

You basically have two common patterns:

Verb + 掉 + Object
- 关掉电脑。
把 + Object + Verb + 掉
- 把电脑关掉。

You don’t normally split it like 关电脑掉. The usual places for the object with this kind of structure:

Without 把: 关掉电脑
With 把: 把电脑关掉

Why don’t we need any tense markers? How do we know this refers to the future (“after work, then do this”)?

Chinese doesn’t mark tense the way English does. Time is shown mainly through:

Time expressions
- 下班以后 clearly points to a time after the workday ends (i.e., future relative to “now” or relative to some reference point).
Sentence type / context
- This is an instruction with 请, so it must be about a future action.

So even without future tense markers, 下班以后请把电脑关掉。 is naturally understood as “Please turn off the computer after (you) get off work (later).”

Could we say 下班了以后 instead of 下班以后? Is there a difference between 以后 and 之后?

You can say 下班了以后, but in this kind of instruction 下班以后 is more natural and concise.

下班以后 = after getting off work.
下班了以后 literally “after (it has) gotten off work,” adding 了 to mark completion, but it’s often redundant here.

以后 vs 之后:

In many contexts, they both mean “after” and are interchangeable:
- 下班以后 / 下班之后 — both okay.
之后 can sound a bit more formal or written in some cases, but the difference here is small.

Is there any difference between 电脑 and 计算机? Which one is more natural here?

Both mean “computer,” but:

电脑 = everyday, colloquial word (what people usually say)
计算机 = more formal/technical, used in written language, subject names, etc.

In this sentence, 电脑 is absolutely the natural, common choice:

下班以后请把电脑关掉。 ✅
下班以后请把计算机关掉。 (sounds like a sign in a lab or technical environment; not normal for everyday speech)

If I want to make this negative, where should I put 不 / 不要?

For a negative instruction (“please don’t turn off the computer”), you can say:

下班以后请不要把电脑关掉。
- 请不要 = “please do not”

Or more direct, less polite:

下班以后不要把电脑关掉。

Placement:

(Time) + (请) + 不要 + 把 + Object + Verb(+掉)

You generally don’t say 请把电脑不要关掉; that sounds wrong. The 不要 should come before 把 in this structure.