Grammar Rule in 30 Seconds
Use 'which' to give more information about objects, animals, or ideas without starting a new sentence.
- Use 'which' only for things and animals, never for people. Example: 'The book which I read.'
- In non-defining clauses (extra info), always use a comma before 'which'. Example: 'My car, which is old, broke.'
- In defining clauses (essential info), 'which' can often be replaced by 'that' in informal English.
Overview
which だ。これはモノ、動物、アイデアをつなぐ究極のコネクターなんだ。2つの関連する考えをくっつける「接着剤」だと思って。そうすれば、5秒ごとに「ピリオド」ボタンを押さずに話を続けられるからね。退屈な2つの文が、1つの洗練された思考に変わって、まるでロンドンやニューヨークに1年住んでたみたいに聞こえるよ。which を使うってことは、名詞にちょっとした「風味」を加えるってこと。文法用語ではこれを関係代名詞（relative pronoun）と呼ぶんだけど、単純に「ポインター（指し示すもの）」だと思えばいいよ。who が君のいつもの仲間（squad）や家族専用なのに対して、which はそれ以外全部を担当するんだ——君のiPhone、近所の野良猫、月曜の朝に感じる実存的な恐怖、頭から離れないTikTokの動画とかね。新しい文を始めなくても、そのモノについてもっと情報を加えられるんだ。英語では、具体的にどのモノを話しているのか定義したり、絶対必要ってわけじゃないけど面白い「おまけ」情報を足したりするのに使うよ。投稿の「編集」ボタンみたいなもんだね。文に戻って、言い忘れた詳細を追加できるんだ。ただ、人間には使っちゃダメだよ。親友がトースター扱いされた気分になっちゃうからね。How This Grammar Works
which は名詞の代わりになるんだ。2つ目の文で名詞を繰り返す代わりに、which に置き換える。例えば、「The laptop is on the table（ノートPCはテーブルの上にある）」と「The laptop is broken（ノートPCは壊れている）」という2つのアイデアがあるとする。「the laptop」を繰り返すんじゃなくて、「The laptop, which is on the table, is broken（テーブルの上にあるノートPCは、壊れている）」と言うんだ。ほら、ずっとスムーズでしょ？which I bought yesterday is amazing.（昨日買ったゲームは最高だ）」。2つ目は「非制限用法（non-defining）」で、無くても生きていけるような追加情報を足す場合。「My car, which is ten years old, still runs perfectly.（私の車は、10年落ちだけど、まだ完璧に走るよ）」。カンマに気づいた？ これは小さな「取っ手」みたいなもので、その追加情報をつまみ上げて、捨てたかったら捨てられるってこと。単なる「ちなみに」程度のコメントならカンマを使う。その情報が、何の話をしているか理解するために不可欠なら、カンマはお家でお留守番。which は状況全体を指すこともあるよ。「He forgot my birthday, which was really annoying.（彼、私の誕生日を忘れてたんだけど、それが本当にムカついた）」。ここでは which は誕生日そのものじゃなくて、「彼が忘れたという事実」を指している。まさに「ドラマ」な代名詞だね。
Formation Pattern
which で文を作るのはレゴセットを組み立てるようなもの。正しい順番に従うだけでいいんだ：
which を足す。
The pizza (（パイナップルがのっていたそのピザは美味しかった。）1),which(3) had pineapple on it (4), was delicious (6).
which 節はできるだけ名詞の近くに置くこと。離しすぎると、何を説明しているのか相手が混乱しちゃうかも。「I saw a cat in the car which was blue.（青い車の中に猫がいた）」とは言わないように。青いのは猫？それとも車？アバター猫じゃない限り、たぶん車のことを言いたかったんだよね。
When To Use It
which の出番だ。こんな時に完璧：- Social Media Captions:
The view,
（息をのむようなその景色は、登った甲斐があった。）whichtook my breath away, was worth the hike. - Product Reviews:
The headphones,
（Amazonで注文したヘッドフォンが、壊れて届いた。）whichI ordered on Amazon, arrived broken. - Professional Emails:
The report,
（最終データを含むレポートを以下に添付します。）whichcontains the final data, is attached below. - Storytelling:
We stayed in a hotel
（幽霊城だったホテルに泊まったんだ。）whichused to be a haunted castle. - Clarifying Choices:
Which is the movie
（君が見たがってた映画はどれだっけ？）（待って、whichyou wanted to see?whichが2回！完全に合法だけど、ちょっとくどいかも。片方をthatにするともっと自然に聞こえるよ。）
that はカジュアルな会話ですごくよく使われるけど、which は「卒論を書いてる大学生」とか「プレゼン中のCEO」っぽい響きがある。正式な手紙やエッセイを書くなら、which は親友になってくれるよ。メール（texting）では？ 使ってもいいけど、カジュアルにしておこう。「The coffee which I just spilled is all over my white shirt. FML.（こぼしたコーヒーが白いシャツにぶちまけられた。最悪。）」
Common Mistakes
- The Human Error: 人に対して
whichを使うこと。「The teacherwhichis nice.」 ✗ ブブー！whoを使って。先生がホログラムじゃない限り、彼らにはwhoを使う権利があるよ。 - Comma Trauma: 追加情報にカンマを忘れること。「My phone
whichis a Samsung is new.」 もし電話を1台しか持ってないなら、カンマが必要だ。「My phone,whichis a Samsung, is new.」 カンマがないと、電話を5台くらい持ってて、そのうちのSamsungのやつを指定してるみたいに聞こえちゃう。 - The Double Subject: 余計な代名詞を足しちゃうこと。「The book
whichI read it was good.」 ✗ ダメ！whichがすでにitの代わりをしてるんだ。代名詞を欲張らないで。 - Which vs. What:
whichの代わりにwhatを使うこと。「The moviewhatI saw.」 ✗ これはすごくネイティブっぽくないか、特定の方言みたいに聞こえる。モノにはwhichかthatを使おう。 - Distance Issues: 名詞と
whichの間に単語を入れすぎること。初デート中のカップルみたいに、近くにいさせてあげて。
Contrast With Similar Patterns
which の最大のライバルは that だ。多くの場合、特にアメリカ英語では、これらは入れ替えて使える。「The car that I want」対「The car which I want」。どっちもOK。でも、秘密のルールがあるんだ。非制限用法（カンマがあるやつ）には only（必ず）which を使わなきゃいけない。「My house, that is red, is on the corner.」とは言えないんだ。 ✗ それは単純に変。which じゃなきゃダメ。who だね。言った通り、who は人用、which はモノ用だ。動物はグレーゾーン。もしペットのポチ（Sparky）なら、who を使おう。彼は家族だもん！ もし公園にいる見知らぬハトなら、which を使おう。where と比べてみよう。where は場所用だけど、前置詞を足せば which も使える。「The house where I live」は「The house in which I live」と同じだ。2つ目はすごくフォーマルで、「ダウントン・アビー」の雰囲気があるね。たいていの人は単に「The house I live in」と言うけど、必要な時に which を使うと上品なかっこよさが出るよ。Quick FAQ
which を質問の始まりに使えますか？
うん、でもそれは別の仕事だね！「Which one do you want?（どっちが欲しい？）」は疑問代名詞だ。ここでの which は関係代名詞で、文をつなぐために使われるよ。
which は that よりもフォーマルですか？
一般的にはそうだね。カジュアルなメールだと、that を使うか、代名詞自体を省略することが多いよ。「The book I read」の方が「The book which I read」より一般的だね。
which は文全体を指すことができますか？
もちろん！「It rained all day, which ruined our picnic.（一日中雨が降って、ピクニックが台無しになった）」この which は雨が降ったという事実全体を指しているよ。
which の前には必ずカンマが必要ですか？
常にじゃないよ。その情報が「おまけ」で、それがなくても文の意味が通じる場合だけだね。
会社について話す場合は？
会社は通常「モノ」として扱われるから、which を使おう。「The company, which was founded in 2010, is now a global giant.（2010年に設立されたその会社は、今や世界的な巨大企業だ。）」
ペットに which を使ってもいい？
冷淡でよそよそしくしたいなら、イエス。もし愛してるなら、who を使ってあげて。
Using 'Which' in Different Roles
| Role | Structure | Example | Notes |
|---|---|---|---|
|
Subject
|
Noun + which + Verb
|
The car which crashed...
|
'Which' acts as the subject.
|
|
Object
|
Noun + which + Subject + Verb
|
The car which I bought...
|
'Which' acts as the object.
|
|
With Preposition (Formal)
|
Noun + Prep + which + Subj + Verb
|
The house in which I live...
|
Common in formal writing.
|
|
With Preposition (Informal)
|
Noun + which + Subj + Verb + Prep
|
The house which I live in...
|
Common in spoken English.
|
|
Sentential
|
Clause + , + which + Verb
|
It rained, which was bad.
|
Refers to the whole situation.
|
Meanings
A relative pronoun used to introduce a relative clause that provides additional information about a noun that is not a person (objects, animals, concepts, or whole situations).
Defining Relative Clause
Used to identify exactly which object we are talking about. The information is essential to the sentence.
“The umbrella which I lost yesterday was blue.”
“Where is the letter which arrived this morning?”
Non-Defining Relative Clause
Used to add extra, non-essential information about an object. It is always separated by commas.
“My house, which was built in 1920, needs repairs.”
“The movie, which lasted three hours, was very boring.”
Sentential Relative Clause
Used to refer back to the entire previous clause or sentence rather than just a single noun.
“He arrived late, which annoyed everyone.”
“She passed the exam, which was a huge relief.”
Reference Table
| 代名詞 | 指すもの | 機能 | 例文 |
|---|---|---|---|
|
who
|
人
|
関係節の主語/目的語
|
The student `who` passed.
|
|
which
|
モノ、動物、考え
|
関係節の主語/目的語
|
The book `which` I read.
|
|
that
|
人、モノ、動物、考え
|
関係節の主語/目的語
|
The car `that` broke down.
|
|
whom
|
人 (正式な目的語)
|
関係節の目的語 (正式)
|
The person `whom` I met.
|
|
whose
|
所有 (人/モノ)
|
所有格
|
The artist `whose` work I admire.
|
フォーマル度スペクトル
The vehicle which was acquired last month is performing well. (Purchasing a car)
The car which I bought last month is running great. (Purchasing a car)
The car I got last month is great. (Purchasing a car)
That ride which I copped is fire. (Purchasing a car)
「Which」を理解しよう
指すもの
- Things 無生物の物
- Animals ペット、野生動物
- Ideas 概念、計画
機能
- Connects Clauses 説明情報を繋ぐ
- Adds Detail 本質的または追加情報を与える
- Avoids Repetition 2つ目の節で名詞を置き換える
文法構造
- `Noun + which + Clause` 標準的なパターン
- Subject/Object 両方の機能を持つ
- Defining Clauses 不可欠な情報
「Who」 vs. 「Which」 vs. 「That」の比較
物に対する適切な関係代名詞の選び方
その名詞は人ですか？
その名詞は物、動物、または考えですか？
その情報は名詞を特定するのに不可欠ですか？
関係代名詞は節の主語ですか？
「Which」の現代的な使われ方
オンラインでの会話
- • 友達とのメッセージ
- • ゲームでのボイスチャット
- • オンラインレビュー
日常生活
- • アプリでの食べ物注文
- • カフェでの会話
- • 問題の説明
学術・専門分野
- • 大学のグループプロジェクト
- • Zoomでの面接
- • 報告書/プレゼンテーション
エンターテイメント
- • Netflixの字幕
- • 映画や番組の話
- • Instagram/TikTokのキャプション
レベル別の例文
I have a car which is red.
I have a car which is red.
This is the book which I like.
This is the book which I like.
The dog which is in the garden is mine.
The dog which is in the garden is mine.
I want the cake which has chocolate.
I want the cake which has chocolate.
The phone which I bought yesterday is broken.
The phone which I bought yesterday is broken.
Is this the bus which goes to the airport?
Is this the bus which goes to the airport?
I lost the keys which were on the table.
I lost the keys which were on the table.
The movie which we saw was very funny.
The movie which we saw was very funny.
My computer, which is quite old, is very slow.
My computer, which is quite old, is very slow.
He forgot my birthday, which made me sad.
He forgot my birthday, which made me sad.
The hotel which we stayed in was near the beach.
The hotel which we stayed in was near the beach.
I need a job which allows me to work from home.
I need a job which allows me to work from home.
The document to which you are referring is lost.
The document to which you are referring is lost.
The city, which was founded in 1200, is famous for its art.
The city, which was founded in 1200, is famous for its art.
They offered me a promotion, which I immediately accepted.
They offered me a promotion, which I immediately accepted.
The criteria by which we judge success are changing.
The criteria by which we judge success are changing.
The proposal, the merits of which are debatable, was rejected.
The proposal, the merits of which are debatable, was rejected.
He was late for the meeting, which fact he failed to mention.
He was late for the meeting, which fact he failed to mention.
The system, which had been failing for years, finally collapsed.
The system, which had been failing for years, finally collapsed.
It was a decision from which there was no turning back.
It was a decision from which there was no turning back.
The treaty, the signing of which heralded a new era, was brief.
The treaty, the signing of which heralded a new era, was brief.
She argued that the law was unjust, which view was widely shared.
She argued that the law was unjust, which view was widely shared.
The company went bankrupt, which outcome surprised no one.
The company went bankrupt, which outcome surprised no one.
We reached the summit at noon, by which time the fog had lifted.
We reached the summit at noon, by which time the fog had lifted.
間違えやすい
Learners often use 'that' after a comma or 'which' without a comma when they shouldn't.
Using 'which' for people or 'who' for objects.
Using 'what' to join two sentences.
よくある間違い
The man which is tall.
The man who is tall.
The book it is good.
The book which is good.
I like the cat who is black.
I like the cat which is black.
The car which it is red.
The car which is red.
The movie what I saw.
The movie which I saw.
The pen which I write with it.
The pen which I write with.
The house where I bought.
The house which I bought.
My car, that is old, broke down.
My car, which is old, broke down.
He was late that was annoying.
He was late, which was annoying.
The city which I live is big.
The city which I live in is big.
The company who's profits are high.
The company, the profits of which are high.
文型パターン
I have a ___ which ___.
The ___ which I ___ is ___.
My ___, which is ___, is ___.
___, which meant that ___.
Real World Usage
I want to return the shoes which I ordered last week.
I am looking for a role which offers growth opportunities.
I lost my phone, which is why I didn't call.
Is this the museum which has the Picasso paintings?
Click the button which is located in the top right corner.
Check out this sunset, which was taken without a filter!
Which for Clarity
No People with Which!
When to Omit Which
(which) I watched...」のように。）でも、「主語」のときは絶対に省略できませんよ！（「The movie which was great...」）「You can sometimes drop which (and that) if it's the *object* of the relative clause, not the subject. For example, 'The movie (which) I watched...' But if which is the subject, keep it! ('The movie which was great...').」Formal vs. Informal
with which」のように前置詞の後に「which」を使うこともありますが、普段の会話では「the device which he fixed with」のように前置詞が最後にくることが多いですよ。「While which with a preposition (e.g., 'the device with which') is grammatically correct and common in formal writing, casual spoken English often prefers moving the preposition to the end ('the device which he fixed with).」Think 'Thing, Animal, Idea'
Smart Tips
Use 'which' instead of 'that' to sound more professional and precise.
Use ', which' at the end of your sentence to share your opinion.
Never use 'that' after a comma in a relative clause. It's always 'which'.
Try removing 'which' to see if the sentence sounds more natural in speech.
発音
The 'wh' sound
In most modern English dialects, 'which' is pronounced exactly like 'witch' /wɪtʃ/. Some older or regional dialects (like Scottish) might use a voiceless 'w' /hw/.
Comma Intonation
In non-defining clauses, there is a slight drop in pitch and a brief pause where the commas are.
Non-defining drop
The cake, ↘ which was chocolate, ↗ was eaten.
The information inside the commas is parenthetical (extra).
暗記しよう
記憶術
W-H-I-C-H: Whatever Has Inanimate Characteristics Here.
視覚的連想
Imagine a giant question mark (?) turning into a bridge. The bridge connects a box (the object) to a label (the description). The bridge is made of the letters W-H-I-C-H.
Rhyme
For a person use 'who', for a thing 'which' will do.
Story
A robot named 'Which' only collects objects. He picks up a 'ball which is round' and a 'box which is heavy'. He never picks up people because he doesn't understand 'who' they are.
Word Web
チャレンジ
Look around your room. Pick 5 objects and describe them using 'which'. (e.g., 'The chair which is near the window is brown.')
文化メモ
American style guides (like APA or Chicago) are very strict about using 'that' for defining clauses and 'which' only for non-defining clauses.
British English is more flexible. It is very common to hear 'which' used in defining clauses where an American would almost always use 'that'.
In academic writing globally, 'which' is preferred for its precision, especially when used with prepositions like 'in which' or 'by which'.
From Old English 'hwilc', which was originally a question word meaning 'of what form'.
会話のきっかけ
What is a movie which you have seen many times?
Tell me about a hobby which you started recently.
Describe a city which you would love to visit.
Think of a problem in your town which needs to be fixed.
日記のテーマ
よくある間違い
Test Yourself
I need the book ___ is on the top shelf.
Find and fix the mistake:
The person which called me was very rude.
Choose the correct sentence:
Translate into English: 'Vi la película que ganó el premio.'
Answer starts with: ["I...
Score: /4
練習問題
8 exercisesThe car ___ I bought is very fast.
Find and fix the mistake:
The man which lives next door is a doctor.
My bike ___ is in the garage is broken.
I have a new phone. It has a great camera.
Paris, that is the capital of France, is beautiful.
A: Why are you upset? B: I lost my wallet, ___.
Select the non-defining clause.
1. The house... 2. He lied... 3. The dog...
Score: /8
Practice Bank
13 exercisesThe laptop ___ I use for work is very fast.
Choose the correct sentence:
Do you know the café ___ has outdoor seating?
Match the subjects with the correct form:
The movie, who was nominated for an Oscar, is streaming now.
Translate into English: 'Ella tiene un perro que siempre duerme en su cama.'
Arrange these words into a sentence:
The concept ___ he explained was quite complex.
I found the keys was under the couch.
Arrange these words into a sentence:
Translate into English: 'El software, sin el cual no podemos operar, requiere una actualización.'
Which sentence demonstrates the most formal use of 'which'?
The painting, you bought, is beautiful.
Score: /13
よくある質問 (8)
No, 'which' is strictly for things, animals, and ideas. For people, always use `who` or `whom`.
Use a comma if the information is 'extra' (non-defining). If the information is essential to identify the object, don't use a comma.
In American English, `that` is preferred for essential information. In British English, both are fine. However, only `which` can be used for extra information after a comma.
Yes, but only if it is the object of the clause (e.g., 'The book (which) I bought'). If it is the subject (e.g., 'The book which is on the table'), you must keep it.
It's when `which` refers to the whole previous sentence, not just one word. Example: 'He won, which surprised us.'
Yes, 'which' is the standard pronoun for animals. However, if the animal is a pet with a name, many people use `who`.
It is slightly more formal than `that` in defining clauses, but it is neutral in most other contexts.
It is a formal way to show possession for things. Example: 'The car, the door of which was open...' (Instead of 'whose door').
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
que / el cual
English distinguishes between 'who' (people) and 'which' (things), whereas Spanish often uses 'que' for both.
qui / que / lequel
French relative pronouns change based on grammatical function (subject/object) rather than person/thing.
der / die / das / welcher
German relative pronouns have gender (masculine/feminine/neuter), while English 'which' is gender-neutral.
Attributive form
Japanese uses word order (modifier before noun) instead of a connecting word like 'which'.
al-ladhi (الذي)
English 'which' is much simpler as it doesn't change for number or gender.
de (的)
The structure is reversed: [Description] + de + [Noun].
Learning Path
Prerequisites
Learn These First
関連動画
08:55 The Land Your State Doesn't Control
09:59 The Biggest Eruptions That Changed Earth Forever
07:46 You Are Not Where You Think You Are
RELATIVE PRONOUNS | RELATIVE CLAUSES | ADJECTIVE CLAUSES - who, which, that, whose, whom
Arnel's Everyday English
WHICH or THAT? A quick and simple guide. Relative clauses explained. English grammar lesson
To The Point English with Ben.
Relative Pronouns | Learn Basic English
English Animated
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