Grammar Rule in 30 Seconds
You can often delete 'that', 'who', or 'which' if they are the object of the following verb.
- Drop it if a new subject follows: 'The movie (that) I saw' is perfect.
- Keep it if it acts as the subject: 'The man who lives here' (cannot drop).
- Keep it in non-defining clauses (extra info with commas): 'My car, which is blue, is old.'
Overview
that、which、who といった関係代名詞で起こるんだ。これらの言葉が説明の object（目的語）として機能するとき、それらはよく姿を消してしまう。まるでメッセージを「既読スルー」されたみたいなものだけど、ここではそれが逆にいいことなんだ。英語がよりスムーズに、より速く、そしてずっと自然に聞こえるようになるからね。もし自分の文章が「ゴツゴツしている」とか、マニュアルを読んでいるロボットみたいだと感じたことがあるなら、これがまさに探していたテクニックだよ。that、which、who といったつなぎの言葉を見かけるよね。例えば、The coffee that I bought was cold.（僕が買ったコーヒーは冷たかった）みたいに。でもちょっと待って。誰かが The coffee I bought was cold.と言っているのを聞いたことがないかな？実は、どちらも正解なんだ。2つ目のバージョンでは、
that という単語が省略されている。これは怠慢じゃない。流暢で自然な英語の標準的な特徴なんだ。Netflixの字幕からTikTokのキャプション、ビジネスメールにいたるまで、どこでもこれを耳にするはず。いつこれらの単語を落とすべきかを理解すれば、教科書っぽさが抜けて、もっと地元の人みたいに聞こえるようになるよ。要は効率の問題だね。短い言葉で済むなら、わざわざ長く言う必要はないよね？ただ、買い物リストでこれをやっちゃダメだよ。「卵、僕が必要な」だと、残念ながらまだ動詞が必要だからね。How This Grammar Works
The pizza that I ordered is here.Iが subject（僕が注文した）。The pizzaが object（それは僕によって注文された）。thatはピザを表している。
I）があるから、この that という代名詞はただの余分な荷物なんだ。だから投げ捨てちゃってOK。実際には歌っていないバックコーラスの人がいるようなものだから、早めに帰らせてあげよう。The guy who called me was annoying.The guyが subject（彼が電話をかけてきた）。whoはその男の人を表している。whoの後、動詞のcalledの前に他の subject はないよね。
who は説明内容の subject なんだ。もしこれを消してしまうと、文章が崩壊する。The guy called me was annoyingは、2つの文が衝突したみたいに聞こえちゃう。仕事に行く途中で文法の玉突き事故なんて起こしたくないよね。
Formation Pattern
the app）。
I downloaded）。
I, you, Sarah, the dog など）があるかチェックする。
that, which, who, whom）は自由に消していいよ。
The song（名詞）+ the DJ（主語）+ played（動詞）
The song the DJ played was a banger.（DJがかけた曲は最高だった）
When To Use It
The show I watched...のほうが、
The show which I watched... よりもずっと自然に聞こえる。友達らしく聞こえるか、法的文書のように聞こえるかの違いだね。
Common Mistakes
- ✗ 間違い:
I know a girl lives in London.
- ✓ 正解:
I know a girl
wholives in London.
lives には subject が必要で、who がその仕事をしているからだ。who を消すと、動詞の lives は一人ぼっちで混乱しちゃう。ハンドルがない自転車に乗ろうとするようなもので、確実に転倒するよ。- フォーマル：
The hotel
in whichwe stayed. - 自然：
The hotel we stayed
in.
which を消すなら、in を前に残しておくことはできない。The hotel in we stayedは、エスプレッソを飲みすぎた人みたいに聞こえるよ。前置詞は節の最後に置こう。中学校の先生が何と言おうと、カジュアルな話し言葉なら、英語は「ぶら下がった」前置詞に意外と寛容なんだ。
Contrast With Similar Patterns
- 省略：
The book I read.
（単に目的語の代名詞thatを消しているだけ）。 - 短縮：
The girl sitting over there.
（who isを消して-ing形を使っている）。
- ✓
My brother,
wholives in NYC, is a chef. - ✗
My brother, lives in NYC, is a chef.
Quick FAQ
代名詞を残しておくのは間違い？
全然そんなことないよ！文法的には完璧だ。ただ、カジュアルな会話だと少しフォーマルすぎたり、堅苦しく聞こえたりするだけ。裏庭のBBQにタキシードを着ていくようなものかな。
whose は消せる？
ダメだよ。whose は所有を表す。これを消すと、「誰が何を持っているか」という情報が失われてしまう。しっかり守ってあげよう。失うには重要すぎる言葉だからね。
whom にも使える？
うん！というか、ほとんどの人は whom が古臭く聞こえるから、そもそも消しちゃうことが多いんだ。80歳以下なら、メッセージで whom と言う必要はおそらくないよ。
that のほうが which よりいい？
現代英語では、モノに対しては that がすごく一般的だ。でも消せるなら、どっちを選ぶかなんてどうでもいいよね。両方消して、一日の次の予定に進もう。
IELTSやTOEFLの試験でこれを使ってもいい？
もちろん、特にスピーキングのセクションではおすすめ。本物の英語を理解していることを示せるからね。ただ、フォーマルなライティング課題では慎重にね。一貫性が大事だから。
もし文章がすごく長かったら？
文章が長くて複雑な場合は、代名詞を残しておくことで、聞き手が君のロジックを追いやすくなることもあるよ。自分の感覚で判断してみて。早口言葉みたいに聞こえるなら、that を戻してあげよう。
When to Drop vs. When to Keep
| Type | Relative Pronoun Role | Rule | Example |
|---|---|---|---|
|
Defining
|
Object
|
Can Drop
|
The car (that) I bought.
|
|
Defining
|
Subject
|
Must Keep
|
The car that hit me.
|
|
Non-Defining
|
Object
|
Must Keep
|
My car, which I bought last year, is red.
|
|
Non-Defining
|
Subject
|
Must Keep
|
My car, which was expensive, is red.
|
Meanings
In English, relative pronouns (who, whom, which, that) can be omitted in defining relative clauses when they function as the object of the clause, making the sentence more concise and natural in speech.
Object Omission
Dropping the pronoun when it represents the person or thing receiving the action in the relative clause.
“The person (who) I met was nice.”
“The book (which) she wrote is a bestseller.”
Prepositional Omission
Dropping the pronoun when it is the object of a preposition, usually moving the preposition to the end of the clause.
“The house (that) we live in is small.”
“The girl (who) I was talking to is my sister.”
Formal Retention
Keeping the pronoun to sound more precise, professional, or academic.
“The individuals whom we interviewed were highly qualified.”
“The data that the study produced is significant.”
Reference Table
| 関係代名詞の役割 | プロンウンありの例 | プロンウンなしの例 | 省略できる？ |
|---|---|---|---|
|
目的語 (動詞の)
|
The car that I bought is red.
|
The car I bought is red.
|
はい
|
|
目的語 (動詞の)
|
The friend whom I met yesterday is kind.
|
The friend I met yesterday is kind.
|
はい (whomの場合)
|
|
目的語 (動詞の)
|
The book which you recommended was great.
|
The book you recommended was great.
|
はい
|
|
主語 (動詞の)
|
The dog that barked is friendly.
|
🚫 誤り: The dog barked is friendly.
|
いいえ
|
|
主語 (動詞の)
|
The person who called me was polite.
|
🚫 誤り: The person called me was polite.
|
いいえ
|
|
主語 (動詞の)
|
The train which arrived late caused delays.
|
🚫 誤り: The train arrived late caused delays.
|
いいえ
|
フォーマル度スペクトル
Is this the document to which you were referring? (Workplace/Office)
Is this the document that you were talking about? (Workplace/Office)
Is this the document you were talking about? (Workplace/Office)
This the one you meant? (Workplace/Office)
関係代名詞の省略
省略できる場合（目的語）
- The book I read The book (that) I read.
- The friend you met The friend (whom/that) you met.
- The movie we watched The movie (that/which) we watched.
省略できない場合（主語）
- The dog that barked The dog (that) barked all night.
- The person who called The person (who) called me.
- The app which crashed The app (which) crashed.
なぜ便利なのか
- 自然に聞こえる Mimics native speaker patterns.
- 簡潔さ Shorter, more direct sentences.
- インフォーマルな状況 Common in everyday speech, texts.
関係代名詞：主語 vs. 目的語
thatは省略できる？
that（またはwho/which）は、限定用法（コンマなし）の関係節の一部ですか？
that（またはwho/which）の『すぐ後』の単語は、別の主語（I、you、名詞など）ですか？
thatを省略する状況
インフォーマルな日常
- • Text messages
- • Casual conversations
- • Social media captions
- • Gaming chats
メディア＆コンテンツ
- • Movie/TV subtitles
- • Blog posts
- • Podcast scripts (casual)
- • Lyrics
ビジネス（時々）
- • Informal emails
- • Project discussions
- • Meeting notes (concise)
- • Technical documentation
レベル別の例文
The book I have is red.
The book (that) I have is red.
The man I see is tall.
The man (who) I see is tall.
The apple you eat is sweet.
The apple (that) you eat is sweet.
The car he drives is fast.
The car (that) he drives is fast.
The phone I bought yesterday is broken.
The phone (that) I bought...
Is this the song you like?
Is this the song (that) you like?
The people we met were very friendly.
The people (who) we met...
I lost the pen you gave me.
I lost the pen (that) you gave me.
The hotel we stayed at was beautiful.
The hotel (that) we stayed at...
The reason I called is to ask for help.
The reason (why/that) I called...
The doctor I talked to was very helpful.
The doctor (who) I talked to...
Everything you said is true.
Everything (that) you said...
The challenges we face are significant.
The challenges (that) we face...
The candidate I voted for didn't win.
The candidate (whom) I voted for...
The apartment they're looking at is too expensive.
The apartment (that) they're looking at...
The advice she's giving you is quite sound.
The advice (that) she's giving you...
The assumptions the author makes are questionable.
The assumptions (that) the author makes...
The speed with which he works is impressive.
Note: Cannot drop 'which' here because the preposition is at the front.
The ease I felt during the presentation surprised me.
The ease (that) I felt...
The level of detail the report provides is sufficient.
The level of detail (that) the report provides...
The sheer audacity the plan required was its undoing.
The audacity (that) the plan required...
Any concerns you might have should be addressed now.
Any concerns (that) you might have...
The nuanced approach the team took saved the project.
The approach (that) the team took...
The very fabric the universe is made of remains a mystery.
The fabric (that) the universe is made of...
間違えやすい
Learners often try to drop the pronoun even when it's the subject of the clause.
Learners confuse 'that' in 'I know that he is coming' with 'that' in 'The book that I bought'.
Learners try to drop pronouns in clauses with commas.
よくある間違い
The girl lives here is my friend.
The girl who lives here is my friend.
The book I like it.
The book I like.
I see man I know.
I see the man I know.
The car that I bought it is blue.
The car I bought is blue.
The man I talked is nice.
The man I talked to is nice.
This is the house which we live.
This is the house we live in.
The movie was good I saw.
The movie I saw was good.
My mother, I love, is a teacher.
My mother, whom I love, is a teacher.
The reason why I'm here for is...
The reason I'm here is...
The person who I gave the book is gone.
The person I gave the book to is gone.
The speed I drove at was safe.
The speed at which I drove was safe.
The way in that he spoke was odd.
The way he spoke was odd.
文型パターン
The ___ I ___ is ___.
Is this the ___ you ___?
I've never seen the ___ she ___.
The ___ we're ___ is ___.
Real World Usage
The link I sent you is dead.
The skills I developed at Google are relevant here.
Is this the pizza I ordered?
The data that the researchers collected was flawed.
Best day I've had in a while!
The property which the tenant occupies...
隠れた主語を見つけよう！
行動するものを捨てないで！
ネイティブの耳を鍛えよう
リアルな英語に近づこう
Smart Tips
This is a 99% signal that you can drop the relative pronoun.
Keep the 'that'. It makes your writing look more organized and professional.
Try to put the noun at the end of the clause. If it fits, it's an object! (e.g., 'The book I read' -> 'I read the book' - Works!)
Native speakers almost ALWAYS drop 'that' after these words.
発音
Rhythm and Stress
When the pronoun is dropped, the stress falls more heavily on the noun and the following subject, creating a faster, more rhythmic 'da-DA da-DA' sound.
Glottal Stop
In some British dialects, if 'that' is kept, the 't' might be replaced by a glottal stop, but dropping it entirely is often preferred for flow.
Rising-Falling
The cake ↗ I made ↘ was good.
Standard declarative statement with a dropped pronoun.
暗記しよう
記憶術
If a Noun or Pronoun is next in line, dropping 'that' is totally fine!
視覚的連想
Imagine a bridge (the word 'that') connecting two islands. If the islands are close enough to touch (Noun + Pronoun), you can remove the bridge and just step across.
Rhyme
When 'that' is the object, don't be a fool, dropping it out is the golden rule.
Story
A busy businessman is running to a meeting. He doesn't have time for extra words. He says 'The report I wrote' instead of 'The report that I wrote' because he is in a hurry. He only keeps 'who' when he talks about 'The man who hired me' because without 'who', the sentence falls apart.
Word Web
チャレンジ
Look at the last 5 text messages you sent. Could you have dropped a 'that' or 'who' in any of them? Rewrite them in your head.
文化メモ
Americans are very likely to drop 'that' in almost all informal and semi-formal speech. Keeping it can sometimes sound slightly 'stiff' or overly emphatic.
While also common, some formal British registers still prefer keeping 'that' or 'which' in written correspondence more than American English does.
In scientific papers globally, keeping the relative pronoun is preferred to ensure there is no ambiguity about what the subject of the sentence is.
In Old English, relative clauses were often formed with the indeclinable particle 'þe'. Over time, 'that' (from the demonstrative 'þæt') took over.
会話のきっかけ
What's the best movie you've seen this year?
Tell me about a person you admire.
Is there a place you've always wanted to visit?
What's the most difficult thing you've ever done?
日記のテーマ
よくある間違い
Test Yourself
This is the gift ___ my friend gave me.
Find and fix the mistake:
The person stole my wallet ran away.
Choose the correct sentence:
Translate into English: 'El coche que compré está en el garaje.'
Answer starts with: ["T...
Score: /4
練習問題
8 exercisesThe man who I saw yesterday is a doctor.
Find and fix the mistake:
The car I bought it is very fast.
The woman ___ lives next door is a pilot.
I liked the movie. You recommended it.
1. The man I saw. 2. The man whom I saw. 3. The man that I saw.
You can drop the relative pronoun in a non-defining relative clause (with commas).
A: Is this the book you were looking for? B: Yes, it's the one ___.
A: The girl who is singing. B: The song she is singing.
Score: /8
Practice Bank
12 exercisesThe concert ___ we saw last night was incredible.
This is the phone ___ has the best camera.
The email arrived this morning contained important news.
Which sentence is correct?
Translate into English: 'El problema que resolvimos era muy complejo.'
Arrange these words into a sentence:
Match the clauses:
She's the only student ___ understood the complex theory.
The solution proposed by the team was innovative.
Select the correct sentence:
Translate: 'La información que necesito está en ese documento.'
Put the words in order:
Score: /12
よくある質問 (8)
No. You can only drop it in defining relative clauses when it is the object. You cannot drop it if it's the subject or in a non-defining clause.
Never! Keeping the pronoun is always grammatically correct. Dropping it is just a way to sound more natural and less formal.
Yes, if 'who' is the object (e.g., 'The man I met'), you can drop it. However, many people prefer to keep 'who' more often than 'that'.
No. You can never drop 'whose' because it shows possession and the sentence would lose its meaning without it.
For writing, it's often better to keep it to show clear structure. For the speaking test, dropping it can help you sound more fluent and natural.
The preposition moves to the end of the relative clause. For example: 'The house (that) I live in'.
English tends toward 'economy of language'. If a word doesn't add new meaning and the sentence is clear without it, we usually remove it.
You can often drop 'when' (The day I met you), but dropping 'where' is much rarer and usually requires adding a preposition (The place I live in).
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
que
Spanish never allows the omission of the relative pronoun.
que / qui
French relative pronouns are strictly mandatory.
der / die / das
German pronouns are inflected and mandatory.
Attributive form
Japanese uses word order instead of pronouns to link ideas.
aladhi (الذي)
Omission depends on the definiteness of the noun, not its role as subject/object.
de (的)
Chinese uses a post-positional linker rather than a relative pronoun.
Learning Path
Prerequisites
Learn These First
関連動画
05:20 Are there really dead wasps in figs? - Carolyn Beans
08:24 Many Crystals Take Millions of Years to Form, Not These
08:10 Drumstick Sundae Jars | Food Wishes
RELATIVE PRONOUNS | RELATIVE CLAUSES | ADJECTIVE CLAUSES - who, which, that, whose, whom
Arnel's Everyday English
Relative Clauses - English Grammar Lesson (Upper Intermediate)
Maltalingua English Language School
Reduced Relative Clauses - Defining and Non- Defining Relative Clauses - Advanced Grammar Lesson
Oxford English Now
Related Grammar Rules
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