Reinaさん
ご質問どうもありがとうございます。
様々な表現があると思いますが、いくつか自然な表現を紹介します.
- Are you already back from work? (もう仕事から、戻ってきたんですか？）
- You already back from work? （同じ意味ですが、ちょっとカジュアルな言い方となっています。文法構造からみれば、ちょっと砕けた言い方だからです）
お好みに合わせて使い分けてみてください。
ご参考にしていただければ幸いです。
"Are you finished already?" is a way of asking if they have completed work or whatever task they were doing. Already, implies that it has happened sooner than expected.
"Did you finish your work early?" is a way to ask if they have completed their work or whatever task they were doing at a time earlier than the usual time.
"You're home already?" implies that you are surprised to see them home already. Already, as mentioned above, implies that it has happened sooner than you expected.
"Are you finished already?"（もう終わったの？）は、仕事や作業が終わったのかどうか尋ねる言い方です。"Already" はそれが予想よりも早かったというニュアンスです。
"Did you finish your work early?"（仕事が早く終わったの？）は仕事や作業がいつもよりも早く終わったのか尋ねる言い方です。
"You're home already?"（もう帰ってきたの？）は、家に帰ってくるのが早くて驚いているニュアンスです。前述の通り、"Already" はそれが予想よりも早かったというニュアンスです。
If you just want to say that you are surprised, you can use the first sentence. This is a statment. It just expresses your surprise.
The second responses are questions that both express surprise and uncertainty. They ask for more information. You can easily add words like "work" or "school" or "practice" to make them more specific.
You can use all of these to express your surprise. Then ask them if they finished early to see if this is the reason why they are back at that time. In colloquial English, you can miss off the 'did' in 'did you finish early' and change it to 'you finished early', and these both mean the same thing. Or you can ask exactly what time the person finished.
"I wasn't expecting you back so soon" Tells the person that you are surprised that they have arrived back from work early.
"How come you're back already?" is a direct way to ask why the person is back earlier than usual.
"I wasn't expecting you back so soon"（今日は帰りが早かったんだね）
は、仕事から帰ってくるのが早くて驚いたと伝えています。
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"How come you're back already?"（何でこんなに早く帰ってきたの？）
は、なぜいつもより帰りが早いのか単刀直入に尋ねています。
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using the term 'already' often applies when surprised or want more emphasis in the sentence, especially in this context where its almost sarcastic to tell them.
When someone comes home earlier than usual, and you want to ask (in a surprised way) something like "You already finished work?" then you may find one of the above suggestions appropriate.
イギリス 
ドイツ 
アメリカ合衆国 
