In the passive voice, “by + the doer” is basic, but some verbs are used with idiomatic expressions containing prepositions other than by. These expressions must be memorized.
Basic Rule
Combinations of the be verb, a past participle, and a particular preposition form fixed idioms. Using “by” may sound unnatural or change the meaning, so it is important to learn the correct preposition for each verb.
Common patterns:
- be interested in (be interested in 〜)
- be surprised at (be surprised at 〜)
- be pleased with (be pleased with 〜)
- be filled with (be filled with 〜)
- be covered with (be covered with 〜)
- be made of / from (be made from 〜: of=the material can be recognized, from=chemical change)
- be known to / for / as (be known to 〜 / be famous for 〜 / be known as 〜)
- be tired of / with / from (be tired of 〜 / become tired with 〜 / be tired from 〜)
I am interested in Japanese culture.（I am interested in Japanese culture）
She was surprised at the news.（She was surprised at the news）
The mountain is covered with snow.（The mountain is covered with snow）
This desk is made of wood.（This desk is made of wood）← the material is visible
Wine is made from grapes.（Wine is made from grapes）← chemical change
Points to Note
① be made of vs be made from: with of, the material can be recognized (a wooden desk → made of wood); with from, the original material has changed and cannot be recognized (grapes → wine).
② Three patterns with be known: to (known to someone, with a person as the subject), for (famous for an ability or characteristic), and as (known as a title or status).
- The actor is known to many people. (He is known to many people)
- Japan is known for its sushi. (Japan is famous for its sushi)
- She is known as a great singer. (She is known as a great singer)
③ be interested in / be surprised at are emotional passives. They originally come from transitive verbs meaning “cause someone to be interested” and “surprise someone,” but their passive forms express “be interested” and “be surprised.”
④ Memorize these expressions as idioms. Since Japanese and English often do not match prepositions directly, learning them as phrases is faster.
- be interested in / surprised at / pleased with
- be filled with / covered with
- be made of (visible material) / be made from (chemical change)
- be known to (people) / for (characteristic) / as (title)
- Memorize them as phrases
Practice
- Write “I am interested in English” in English.
- Write “She was surprised at the news” in English (news).
- Write “Cheese is made from milk” in English (cheese / milk).