qǐng nǐ jìnmén yǐhòu bǎ mén guānshàng ba.

请 is often used to make a polite request, similar to please in English.

So 请你…… means something like:

• please, you…
• would you please…

In natural English, we would not say please you, but in Chinese this structure is normal.

In this sentence, 请你进门以后把门关上吧 is a polite way to say:

• Please close the door after you come in.

The 你 is not always necessary. You could also say:

• 请进门以后把门关上。

But 请你 can make it feel a bit more direct toward the listener.

以后 means after.

Chinese often puts 以后 after the event it refers to:

• 进门以后 = after entering the door / after coming in

So the pattern is:

• [event] + 以后 = after [event]

Examples:

• 吃饭以后 = after eating
• 下课以后 = after class ends
• 到家以后 = after arriving home

So here:

• 你进门以后 = after you come in

This is different from English, where after usually comes before the event.

把 is used to bring the object in front of the verb when the speaker wants to emphasize what happens to that object.

So:

• 把门关上 literally means something like take the door and close it

A more natural English translation is just:

• close the door

The 把 construction is very common when:

1. the object is specific and known
2. the verb affects the object clearly
3. there is often a result or direction after the verb

Here, 门 is a specific object, and 关上 shows the result: the door becomes shut.

That is why 把 fits very naturally here.

关 means to close.

关上 means to close completely / to shut.

The 上 here is a result complement. It shows that the action reaches its intended result.

So:

• 关门 = close the door
• 关上门 = shut the door, close it fully

In many cases, both are possible, but 关上 sounds a bit more complete and definite.

Other similar examples:

• 打开 = open up
• 写完 = finish writing
• 拿出来 = take out

So in this sentence, 关上 emphasizes the result that the door ends up closed.

吧 softens the tone.

Without 吧, the sentence can sound more direct:

• 请你进门以后把门关上。

With 吧, it sounds gentler, more like a polite suggestion or request:

• 请你进门以后把门关上吧。

In this kind of sentence, 吧 is often similar to:

• okay?
• please do
• a softened request tone

It does not change the basic meaning much, but it makes the sentence sound more natural and less stiff.

The two 门 are doing different jobs.

1. 进门
   Here, 进门 is a set expression meaning enter the door / come in.

2. 把门关上
   Here, 门 is the object of 关上: close the door.

So even though the same character appears twice, the roles are different:

• first: part of 进门 = come in
• second: the door that gets closed

This repetition is completely normal in Chinese.

Yes, but the structure would change.

For example:

• 请你进门以后关上门吧。

This is also correct and natural.

Compare:

• 把门关上
• 关上门

Both mean close the door.

The 把 version puts extra focus on the object 门 and on what happens to it. It is especially common when the action produces a clear result.

So:

• 请你进门以后把门关上吧。
• 请你进门以后关上门吧。

Both are fine. The first one highlights the object a little more.

Chinese word order usually goes from:

1. topic / subject
2. time or condition
3. manner / object structure
4. verb phrase

So here the order is:

• 请你 = polite request to you
• 进门以后 = after you come in
• 把门关上 = close the door
• 吧 = soften the request

This is a very normal Chinese order:

• [after doing X], do Y

So:

• 你进门以后，把门关上。

Trying to put 把门 before 进门以后 would sound unnatural because 进门以后 is the time/condition for the whole action.

Yes, literally it is something like enter the door, but in natural usage it simply means:

• come in
• enter

Chinese often uses compact verb-object combinations like this.

Examples:

• 上车 = get in the car / board
• 下楼 = go downstairs
• 回家 = go home
• 进门 = come in, enter through the door

So while the literal meaning is useful to notice, the natural meaning here is just come in.

Yes. 后 and 以后 can both mean after.

So these are both fine:

• 你进门后，把门关上吧。
• 你进门以后，把门关上吧。

In many everyday sentences, they are very similar.

Very roughly:

• 后 is shorter and a little more compact
• 以后 can sometimes sound slightly fuller or more explicit

But in this sentence, both are natural.

Because this is a request, not a completed action.

了 is often used to talk about change or completion, but here the speaker is telling someone what to do in the future:

• Please close the door after you come in.

Since the action has not happened yet, 了 is not needed.

In commands and requests, Chinese often uses:

• 请
• 吧
• sometimes just the verb phrase by itself

So 关上吧 sounds natural, while adding 了 here would usually not be the normal choice.

Yes, absolutely.

This version is very natural:

• 你进门以后，请把门关上吧。

It means the same thing.

The difference is mostly about rhythm and emphasis:

• 请你进门以后把门关上吧。
  starts with the request marker 请
• 你进门以后，请把门关上吧。
  first sets up the time condition after you come in, then gives the request

Both are correct and commonly understandable.