関係代名詞と接続詞は、短い文をつなげて詳しい情報を伝えるための重要な文法だよ。これがマスターできれば、長文読解も楽になるし、自分でも複雑で表現力豊かな文が作れるようになる。
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Updated Mar 27, 2026
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簡単に学ぶ関係代名詞と接続詞の使い方
1 / 6
関係代名詞と接続詞の基本概念
関係代名詞って聞くと難しそうだけど、実は接着剤みたいなもの。前の名詞（先行詞）をより詳しく説明する文をくっつける役割をしているんだ。
先行詞が「人」か「人以外」かで使う関係代名詞が変わるから、まずこれを見つけることがポイント。「友達が住んでいる」みたいに、関係代名詞が主語の働きをするのが主格、「私が買った本」みたいに目的語になるのが目的格だよ。
接続詞は文と文をつなぐ役割。and, butのように対等につなぐ等位接続詞と、when, ifのように片方の文を主文に従属させる従属接続詞がある。
💡 覚えておこう: 先行詞を見つけることが関係代名詞攻略の第一歩！
関係代名詞の種類と使い分け
関係代名詞の選び方は簡単。先行詞が人か人以外かと、主格か目的格かで決まるんだ。
人が先行詞ならwho（主格）、whom/who（目的格）。人以外ならwhich。thatは人でも人以外でも使えて便利だけど、所有格では使えないから注意しよう。
主格の作り方は2つの文の共通部分を見つけて、2文目の主語を関係代名詞に変えるだけ。「I have a friend. + He lives in Osaka. → I have a friend who lives in Osaka.」みたいな感じ。
目的格も同じ要領で、2文目の目的語を関係代名詞に変える。重要なのは、目的格の関係代名詞は省略できることが多いってこと。
💡 テストのコツ: 目的格の関係代名詞が省略されている可能性も考えよう！
関係代名詞whatと接続詞の使い分け
whatは他の関係代名詞と全然違って、先行詞を含んでいるのが最大の特徴。「〜すること・もの」と訳して、「what = the thing(s) which」と覚えておこう。
「What he said is true.（彼が言ったことは本当だ）」みたいに使う。thatとwhatの使い分けは超重要で、先行詞があるならthat/which、先行詞がないならwhatを選ぼう。
接続詞は意味でグループ分けすると覚えやすい。時（when, while）、理由（because, since）、条件（if, unless）、譲歩（though, although）の4つが基本パターン。
名詞節を作るthatは関係代名詞のthatとは別物。「I think that English is fun.」のthatは「〜ということ」という意味で、よく省略される。
💡 重要ポイント: 先行詞の有無でwhatとthat/whichを使い分けよう！
実践的な文の作り方
実際に文を作って練習してみよう。「私は昨日駅で会った男性を知っています」を例にすると、2つの文「I know the man」と「I met him at the station」を組み合わせる。
共通部分はthe manとhim。先行詞がthe man（人）で、himは目的語だから目的格を使う。「I know the man whom/who/that I met at the station yesterday」または省略形「I know the man I met at the station yesterday」、どれでもOK。
whatを使う文も簡単。「彼が欲しいものは新しいコンピューターです」なら、先行詞がないからwhatを使って「What he wants is a new computer」になる。
接続詞の例では、「雨が降っていたけれども、私たちはサッカーをした」は譲歩なので「Though it was raining, we played soccer」。文の順番は前後どちらでも大丈夫だよ。
💡 練習のコツ: まず2つの文に分けて考えると、関係代名詞が使いやすくなる！
テストで差がつくポイント
関係代名詞の格を間違えないのが最重要。後ろの文で主語の働きなら主格、目的語なら目的格。直後に動詞が来るか「主語+動詞」が来るかで判断しよう。
thatが使えない場合を覚えておくのも大切。カンマの後（非制限用法）と前置詞の直後ではthatは使えない。「My brother, who lives in Kyoto」のwhoはthatに変えられないんだ。
関係代名詞のthatと接続詞のthatの見分け方もマスターしよう。関係代名詞は前に名詞があって、後ろの文が不完全。接続詞は前に動詞があることが多くて、後ろの文が完全だよ。
時や条件の副詞節では、未来のことでも現在形を使う。「I will call you when I arrive（×will arrive）」みたいに、これはテストの定番問題だから要注意。
💡 テスト対策: 時・条件の副詞節は未来でも現在形！忘れがちだから特に注意しよう。
まとめと応用のコツ
関係代名詞は先行詞（人か人以外か）と格（主格か目的格か）で使い分ける。who（人）、which（人以外）、that（両方OK）が基本で、whatは先行詞を含む特別な関係代名詞だった。
目的格の関係代名詞は省略できるのも重要ポイント。長文読解でよく出てくるから、「あれ、何かが省略されてる？」って気づけるようになろう。
接続詞は意味のカテゴリー（時、理由、条件、譲歩など）で覚えるのがベスト。thatには関係代名詞と接続詞の2種類があるから、文の構造をしっかり見て判断することが大切。
これらの文法をマスターすれば、英語の表現力が格段にアップする。短い文ばかりじゃなく、情報豊かな長い文も自由自在に作れるし、読めるようになるよ！
💡 上達のカギ: 最初は簡単な文から始めて、少しずつ複雑な文に挑戦していこう！
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Most popular content in 英語コミュニケーション
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Students love us — and so will you.
4.6/5
App Store
4.7/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
簡単に学ぶ関係代名詞と接続詞の使い方
関係代名詞と接続詞は、短い文をつなげて詳しい情報を伝えるための重要な文法だよ。これがマスターできれば、長文読解も楽になるし、自分でも複雑で表現力豊かな文が作れるようになる。
関係代名詞と接続詞の基本概念
関係代名詞って聞くと難しそうだけど、実は接着剤みたいなもの。前の名詞（先行詞）をより詳しく説明する文をくっつける役割をしているんだ。
先行詞が「人」か「人以外」かで使う関係代名詞が変わるから、まずこれを見つけることがポイント。「友達が住んでいる」みたいに、関係代名詞が主語の働きをするのが主格、「私が買った本」みたいに目的語になるのが目的格だよ。
接続詞は文と文をつなぐ役割。and, butのように対等につなぐ等位接続詞と、when, ifのように片方の文を主文に従属させる従属接続詞がある。
💡 覚えておこう: 先行詞を見つけることが関係代名詞攻略の第一歩！
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
関係代名詞の種類と使い分け
関係代名詞の選び方は簡単。先行詞が人か人以外かと、主格か目的格かで決まるんだ。
人が先行詞ならwho（主格）、whom/who（目的格）。人以外ならwhich。thatは人でも人以外でも使えて便利だけど、所有格では使えないから注意しよう。
主格の作り方は2つの文の共通部分を見つけて、2文目の主語を関係代名詞に変えるだけ。「I have a friend. + He lives in Osaka. → I have a friend who lives in Osaka.」みたいな感じ。
目的格も同じ要領で、2文目の目的語を関係代名詞に変える。重要なのは、目的格の関係代名詞は省略できることが多いってこと。
💡 テストのコツ: 目的格の関係代名詞が省略されている可能性も考えよう！
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
関係代名詞whatと接続詞の使い分け
whatは他の関係代名詞と全然違って、先行詞を含んでいるのが最大の特徴。「〜すること・もの」と訳して、「what = the thing(s) which」と覚えておこう。
「What he said is true.（彼が言ったことは本当だ）」みたいに使う。thatとwhatの使い分けは超重要で、先行詞があるならthat/which、先行詞がないならwhatを選ぼう。
接続詞は意味でグループ分けすると覚えやすい。時（when, while）、理由（because, since）、条件（if, unless）、譲歩（though, although）の4つが基本パターン。
名詞節を作るthatは関係代名詞のthatとは別物。「I think that English is fun.」のthatは「〜ということ」という意味で、よく省略される。
💡 重要ポイント: 先行詞の有無でwhatとthat/whichを使い分けよう！
Sign up to see the contentIt's free!
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Improve your grades
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実践的な文の作り方
実際に文を作って練習してみよう。「私は昨日駅で会った男性を知っています」を例にすると、2つの文「I know the man」と「I met him at the station」を組み合わせる。
共通部分はthe manとhim。先行詞がthe man（人）で、himは目的語だから目的格を使う。「I know the man whom/who/that I met at the station yesterday」または省略形「I know the man I met at the station yesterday」、どれでもOK。
whatを使う文も簡単。「彼が欲しいものは新しいコンピューターです」なら、先行詞がないからwhatを使って「What he wants is a new computer」になる。
接続詞の例では、「雨が降っていたけれども、私たちはサッカーをした」は譲歩なので「Though it was raining, we played soccer」。文の順番は前後どちらでも大丈夫だよ。
💡 練習のコツ: まず2つの文に分けて考えると、関係代名詞が使いやすくなる！
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
テストで差がつくポイント
関係代名詞の格を間違えないのが最重要。後ろの文で主語の働きなら主格、目的語なら目的格。直後に動詞が来るか「主語+動詞」が来るかで判断しよう。
thatが使えない場合を覚えておくのも大切。カンマの後（非制限用法）と前置詞の直後ではthatは使えない。「My brother, who lives in Kyoto」のwhoはthatに変えられないんだ。
関係代名詞のthatと接続詞のthatの見分け方もマスターしよう。関係代名詞は前に名詞があって、後ろの文が不完全。接続詞は前に動詞があることが多くて、後ろの文が完全だよ。
時や条件の副詞節では、未来のことでも現在形を使う。「I will call you when I arrive（×will arrive）」みたいに、これはテストの定番問題だから要注意。
💡 テスト対策: 時・条件の副詞節は未来でも現在形！忘れがちだから特に注意しよう。
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
まとめと応用のコツ
関係代名詞は先行詞（人か人以外か）と格（主格か目的格か）で使い分ける。who（人）、which（人以外）、that（両方OK）が基本で、whatは先行詞を含む特別な関係代名詞だった。
目的格の関係代名詞は省略できるのも重要ポイント。長文読解でよく出てくるから、「あれ、何かが省略されてる？」って気づけるようになろう。
接続詞は意味のカテゴリー（時、理由、条件、譲歩など）で覚えるのがベスト。thatには関係代名詞と接続詞の2種類があるから、文の構造をしっかり見て判断することが大切。
これらの文法をマスターすれば、英語の表現力が格段にアップする。短い文ばかりじゃなく、情報豊かな長い文も自由自在に作れるし、読めるようになるよ！
💡 上達のカギ: 最初は簡単な文から始めて、少しずつ複雑な文に挑戦していこう！
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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Students love us — and so will you.
4.6/5
App Store
4.7/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user