落としましたよ

you dropped it

→ 落とす
phrase Uncommon #17,874
you dropped it A polite way to alert someone that they have dropped something. The subject is often omitted; depending on context, it can also mean “I dropped it.” The よ adds emphasis, like “you know” or “just so you know.”
JA: すみません、鍵を落としましたよ。
EN: Excuse me, you dropped your keys.

あのすみませんが落としましたよ

Um... excuse me... you dropped this.

— アトランティス 失われた帝国 (2001)

財布落としましたよ

You dropped your wallet.

落としましたよ

You dropped your keys.

鉛筆を落としましたよ

You dropped your pencil.