sigoto ga kanryousimasita.

が marks 仕事 as the grammatical subject of the sentence.

So in 仕事が完了しました, the thing that became completed is the work/task.

A very literal breakdown is:

• 仕事 = work, job, task
• が = subject marker
• 完了しました = was completed / has completed

In natural English, we often say The work has been completed or The task is complete.

Japanese often uses が when introducing or identifying what has a certain state. Here, the state is completed.

完了しました uses the verb 完了する, which means to be completed / to complete depending on context.

So:

• 完了です = it is complete
• 完了しました = it has completed / it was completed

The version with しました sounds a bit more like the completion has happened, while 完了です sounds more like the current status is complete.

In many real situations, both can work, but the nuance is slightly different:

• 仕事が完了です → a status statement
• 仕事が完了しました → completion has occurred

The sentence you were given sounds like a formal announcement or status update.

It looks active because of しました, but in meaning it often works like an intransitive completion statement in context.

This can confuse English speakers.

Japanese sometimes expresses things in a way that does not match English active/passive patterns exactly. Here, 仕事が完了しました means something like:

• The work has been completed
• The task is now complete

Even though English often prefers a passive translation, the Japanese sentence itself is not using the normal passive form.

A more clearly active sentence would be:

• 仕事を完了しました = I/we completed the work

That version uses を, marking 仕事 as the object of the action.

This is a very important difference.

• 仕事が完了しました
  = The work has been completed.
  Focus: the work reached a completed state.

• 仕事を完了しました
  = I/we completed the work.
  Focus: someone performed the action of completing the work.

So the particle changes the perspective:

• が → focuses on what is in that state
• を → focuses on what someone acted on

If you are reading a system notification, report, or formal notice, 仕事が完了しました is very natural because it emphasizes the result, not the person who did it.

Japanese often leaves out the doer when it is obvious, unimportant, or intentionally unstated.

In 仕事が完了しました, the sentence only tells you that the work is completed. It does not explicitly say who completed it.

Depending on context, it could mean:

• I completed it
• We completed it
• Someone completed it
• The system/process finished it

This omission is very normal in Japanese. English often wants a clear subject like I, we, or it, but Japanese often does not require one if the context already makes it clear.

It depends on context.

仕事 can mean:

• work
• job
• task
• piece of work

In this sentence, it often sounds closest to work or task.

Examples:

• In an office status message: The task has been completed
• In a general statement: The work has been completed

It usually does not mean my career/job here. It refers more to a specific piece of work or assigned work that can be finished.

It is polite and somewhat formal.

Why?

• 完了しました uses the ます-form past tense, which is polite.
• 完了 is a somewhat formal word compared with more everyday alternatives.

This kind of sentence is common in:

• business Japanese
• written notices
• software/system messages
• reports
• formal updates

In casual speech, a person might say something simpler, such as:

• 仕事終わったよ。 = The work is done.
• 終わった。 = It’s finished.

So 仕事が完了しました sounds more official than casual conversation.

The dictionary form is 完了する.

Conjugation:

• dictionary form: 完了する
• polite non-past: 完了します
• polite past: 完了しました

So:

• 完了する = to complete / to be completed
• 完了しました = completed / has been completed

Because する is attached to the noun 完了, this is a suru-verb.

A lot of formal Japanese verbs work this way:

• 開始する = to begin
• 終了する = to end
• 確認する = to confirm
• 完了する = to complete

Yes, and in many cases that sounds more natural in everyday Japanese.

Compare:

• 仕事が終わりました = The work finished / the work is done
• 仕事が完了しました = The work has been completed

Difference in nuance:

• 終わりました is more common and everyday.
• 完了しました is more formal, technical, or status-oriented.

For example:

• Talking to a friend or coworker casually: 仕事が終わりました
• In a report, interface message, or official notice: 仕事が完了しました

So both are correct, but they fit different situations.

This is a very common question.

Japanese past tense often indicates that a change has occurred. So 完了しました means that the completion happened, and as a result, the work is now complete.

That is why it can be translated as:

• The work was completed
• The work has been completed
• The work is now complete

English chooses different forms depending on style and context, but Japanese is simply marking that the event of completion already happened.

Yes, but it sounds most natural in formal or written contexts.

It is especially natural in:

• business reports
• task management systems
• workflow notifications
• technical writing

Examples of where you might see it:

• 仕事が完了しました。
• 処理が完了しました。 = Processing has completed.
• インストールが完了しました。 = Installation has completed.

In everyday conversation, people often use simpler wording instead.

The spaces are probably added for learners.

Normally, Japanese is written without spaces, so this would usually appear as:

仕事が完了しました。

Textbooks and beginner materials sometimes insert spaces to help learners see the parts more clearly:

• 仕事
• が
• 完了しました

But in normal Japanese writing, you should expect no spaces.

Yes, absolutely. In fact, it often sounds like a system or status message.

Because the sentence does not mention a person and focuses on the result, it works very well for:

• software notifications
• automated emails
• workflow systems
• process updates

For example:

• ダウンロードが完了しました。 = The download has completed.
• 更新が完了しました。 = The update has completed.

So 仕事が完了しました could easily be a message in a work management tool saying that a task is complete.

The basic order is:

noun + particle + verb

So:

• 仕事 = work
• が = subject marker
• 完了しました = completed

Japanese usually puts the main verb at the end. That is one of the biggest differences from English.

A very literal order would be:

Work + subject marker + completed

Natural English then rearranges that into something like:

The work has been completed.