Explanation
Use the passive voice with an agent when you want to focus on the thing, not the person who did it.
In "The cake was made by my mother.", "The cake" is the subject, "was" is the be verb, "made" is the past participle, and "by my mother" tells us who did the action. English often uses this when the doer is less important, or when you want to sound polite or formal. Japanese often says "母がケーキを作りました" with the doer first, but English can move the thing to the front. If you mention the doer in English passive, use "by".
行為した人より、物や出来事を目立たせたいときに受け身＋行為者を使います。
例えば "The cake was made by my mother." では、"The cake" が主語、"was" が be 動詞、"made" が過去分詞、"by my mother" が「だれが作ったか」を表します。英語では、作った人が重要でないときや、丁寧・客観的に言いたいときによく使います。日本語では「母がケーキを作りました」のように行為者を先に言うことが多いですが、英語では物を前に出せます。受け身で行為者を入れるときは、必ず "by" を使います。
Examples
- The cake was made by my mother. そのケーキは母が作りました。
- This song was written by a famous singer. この歌は有名な歌手によって書かれました。
- The room is cleaned by the staff every morning. その部屋は毎朝、スタッフによって掃除されます。
- Was this photo taken by you? この写真はあなたが撮ったのですか。
- My bike was not fixed by the shop. 私の自転車はその店では直されませんでした。
- The tickets will be checked by the guard at the door. チケットは入口で警備員が確認します。
Common Mistakes
Japanese learners often forget the be verb or use the wrong preposition. For example, "The cake made by my mother" is missing "was," and "The cake was made from my mother" uses the wrong word. Say "The cake was made by my mother."
日本語話者は、be 動詞を落としたり、前置詞を間違えたりしやすいです。たとえば "The cake made by my mother" は "was" が抜けていますし、"The cake was made from my mother" は前置詞が違います。正しくは "The cake was made by my mother." です。