「忘れ物を取りに来ました」という文章を英語で伝えると「I came back to get something I forgot.」または「I returned to get something I left behind.」と言っても良いと考えました。「忘れ物」という言葉は「something I forgot」または「something I left behind」になって、「取りに来ました」という表現は 「came back」または「returned」になります。
1. I'm here to get my notebook which I forgot.
This statement means that the reason that you returned was to get something that you accidently forget.
2. I came back to get something that I forgot.
The expression "came back" is another way of saying that you returned to place that you had previously left.
Example:-
Teacher: Hi Sandy, I thought I saw you leave the classeoom 5 minutes ago.
Student: Yes teacher, I came back to get something that I forgot.
1. I'm here to get my notebook which I forgot.（ノートを忘れたので取りに来ました）
これは、忘れ物をしたので戻ってきたという意味です。
2. I came back to get something that I forgot.（忘れ物を取りに戻ってきました）
"come back"は、元いた場所に戻ってくるという意味です。
【例文】
先生: Hi Sandy, I thought I saw you leave the classeoom 5 minutes ago.
（やあ、サンディ、5分前に教室を出たように思ったけど）
生徒: Yes teacher, I came back to get something that I forgot.
（はい、先生。忘れ物を取りに戻ってきました）
I believe I left something in the room! May I look for it, please?
1. "I forgot something! I need to go back for it!"
Something - this can refer to a book, phone, keys, coffee cup, etc /
Go back for it - Meaning you need to return to get what you forgot.
2. "I believe I left something in the room! May I look for it, please?"
Believe I left something - Use this expression if you have lost something and you think you know where you left it.
May I look for it, please? - If you think you left the item at a friend's house, in a classroom, office, etc., you can use this expression to ask for permission to look for the item you lost/forgot. Always remember to be polite and say "Please."
例文
1. "I forgot something! I need to go back for it!"
（忘れ物をしました。取りに帰らないと）
Something - 本・電話・鍵・コーヒーカップなどを表します
Go back for it - 忘れ物を取りに戻るということです
例文
2. "I believe I left something in the room! May I look for it, please?"
（部屋に忘れ物をしました。探しに行ってもいいですか？）
Believe I left something - これは、忘れ物をして、どこに忘れたか見当が付いているときに使います
May I look for it, please? - 友達の家・教室・オフィスなどに忘れ物をしたなら、この表現を使って探しに行く許可を求めることができます。必ず、丁寧に"Please"と言うようにしましょう。
"Don't mind me" is a casual way to say that the other person does not need to pay attention to you.
"I just came back to get _______." provides a brief statement about why you are there.
"Don't mind me"は、「私のことは気にしないでください」と伝えるカジュアルな言い方です。
"I just came back to get _______."（～を取りに来ただけです）は、自分がそこにいる理由を簡潔に伝えています。
You could approach your teacher and say, "I came back to get my "book" that I forgot. Or you could say, "I forgot something, do you mind if I grab it?"
例えば、先生の所に行って、
"I came back to get my "book" that I forgot."
（本を忘れて取りに来ました）
と言えます。
あるいは、次のように言うこともできます。
"I forgot something, do you mind if I grab it?"
（忘れ物をしました。取りに行ってもいいですか）
Something slipped my mind and I came back to get it.
I completely forgot something so I had to come back to get it.
The two sentences you see provided above are excellent ways to express to your listener that you forgot something and you had to come back to get it. In the first sentence you will see the phrase slip one's mind. This means to forgot. This is a phrase that is appropriate for informal settings and it would make a great addition to your vocabulary.
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