wǒ xiěwán bàogào yǐhòu jiù qù shuìjiào.

写完 is a verb + result complement structure.

• 写 = to write
• 完 = to finish, to complete

So 写完 means to finish writing.

In Mandarin, it is very common to put a result word after a verb to show the outcome of the action. Here, 完 tells you that the writing is completed, not just in progress.

Compare:

• 我写报告。 = I write / am writing a report.
• 我写完报告。 = I finish writing the report.

Because in Chinese, the result complement usually comes directly after the verb, before the object if the object is simple.

So the natural pattern is:

• 写完报告 = finish writing the report

not:

• 写报告完 ✘

This is a common structure:

• 吃完饭 = finish eating a meal
• 看完书 = finish reading a book
• 做完作业 = finish doing homework

So 写完报告 follows the normal pattern.

以后 means after or afterward.

In this sentence, it comes after a clause:

• 写完报告以后 = after finishing the report

So the pattern is:

• [event] + 以后 = after [event]

Examples:

• 下班以后 = after getting off work
• 吃饭以后 = after eating
• 回家以后 = after going home

Here, 以后 links the first action to the next one.

就 often shows that the next action happens then, right away, as a natural next step, or soon after.

So:

• 写完报告以后去睡觉 = after finishing the report, go to sleep
• 写完报告以后就去睡觉 = after finishing the report, then / right away go to sleep

In this sentence, 就 adds a sense of sequence and immediacy: once the report is done, going to sleep is the next thing.

No, it is not strictly required, but it is very natural.

Without 就:

• 我写完报告以后去睡觉。

This is still grammatical and understandable. It simply states the order of events.

With 就:

• 我写完报告以后就去睡觉。

This sounds more natural in many contexts and emphasizes that sleeping follows right after finishing the report.

Because the subject is the same in both parts of the sentence, Chinese often omits the repeated subject.

So:

• 我写完报告以后就去睡觉。
• literally: I, after finishing the report, then go sleep.

You could say:

• 我写完报告以后，我就去睡觉。

But repeating 我 is usually unnecessary here unless you want extra emphasis or a clearer pause.

Because 完 already shows the result of the action, and Chinese does not always need 了.

了 can be added in some contexts, but it is not mandatory every time a completed action is mentioned.

For example:

• 我写完报告以后就去睡觉。 = natural
• 我写完了报告以后就去睡觉。 = also natural

The version with 了 may sound a bit more explicitly completed, but both work.

So:

• 完 = completion as a result complement
• 了 = perfective marker, often marking a completed event in context

They can appear together, but they do not always have to.

Yes, in many cases, but there are small differences in style and naturalness.

Possible alternatives:

• 我写完报告以后就去睡觉。
• 我写完报告之后就去睡觉。
• 我写完报告后就去睡觉。

All are grammatical.

General tendency:

• 以后 = very common in everyday speech
• 之后 = slightly more formal or written-sounding
• 后 = shorter, often used in writing or concise speech

For a learner, 以后 is a very safe and natural choice.

睡觉 literally means to sleep, but in many everyday situations it is used like go to bed or go sleep.

So in this sentence, 去睡觉 means:

• go to sleep
• go to bed
• go get some sleep

The exact English translation depends on context, but the Chinese expression is very common and natural.

去 literally means to go, but it is often used before another action to mean go and do something.

So:

• 去睡觉 = go to sleep / go and sleep
• 去吃饭 = go eat
• 去工作 = go work

It does not always strongly emphasize physical movement. Sometimes it just introduces the next action in a natural way.

In this sentence, 就去睡觉 means then go to sleep.

The sentence follows this pattern:

• Subject + [finish doing action A] + 以后 + 就 + action B

Applied here:

• 我 = subject
• 写完报告 = finish writing the report
• 以后 = after
• 就 = then / right away
• 去睡觉 = go to sleep

So the overall structure is:

• After I finish writing the report, I’ll then go to sleep.

This is a very common way to talk about two actions in sequence.

Yes. Chinese often relies on context instead of a special future tense.

This sentence can mean something like:

• After I finish the report, I’ll go to sleep
• Once I’m done writing the report, I’m going to bed

There is no need for a word like will in every sentence. If the context is about a future plan, the sentence is naturally understood that way.

You usually would not say 等...以后 together in this way, because that can sound redundant.

More natural choices are:

• 我写完报告以后就去睡觉。
• 等我写完报告，我就去睡觉。

Both mean roughly the same thing, but the structures are different:

• 以后 = after
• 等 = wait until / when

So use one pattern or the other, rather than combining both.

Chinese nouns often do not mark the vs a explicitly. So 报告 could mean:

• the report
• a report
• my report, depending on context

The sentence itself does not force one interpretation. English usually requires an article, but Chinese often leaves that unspecified unless the context makes it clear.

The original order is the most natural for this meaning.

• 我写完报告以后就去睡觉。

You can also front the time clause for emphasis:

• 写完报告以后，我就去睡觉。

This is also very natural.

But changing the internal order too much can make it wrong or unnatural. For example, keep these parts together:

• 写完报告
• 以后
• 就去睡觉

So while Chinese allows some flexibility, the main grammar relationships should stay intact.