Grammar Rule in 30 Seconds
The verb 'to be' is the 'glue' of English, connecting a person or thing to a description, name, or location.
- Use `am` only with `I` (e.g., I am happy).
- Use `is` for one person/thing (he, she, it) (e.g., She is a doctor).
- Use `are` for you and groups (you, we, they) (e.g., We are students).
Overview
to be なしでは、それは不可能です。これは英語という言語の絶対的なエンジンです。これがないと、あなたはただ空間を浮遊している名詞と形容詞の集まりにすぎません。to be は、あなたのアイデンティティと言葉をくっつける接着剤のようなものだと考えてください。それはあなたが誰で、どこにいて、今どう感じているかを世界に伝えます。I am tired というキャプションで自撮りを投稿するときも、Uberドライバーのステータスを確認するときも、あなたはこのルールを使っています。これは英語で本物の人間のように話すための第一歩です。心配しないでください、複雑なRPGでレベルアップするよりもずっと簡単です。少しの練習といくつかの記憶のコツが必要なだけです。How This Grammar Works
to be にあたる動詞を省略することがあるかもしれません。しかし、英語では決して省略しません。これは数学の式の等号（＝）のように機能します。I ＝ happy。You ＝ at home。動詞 to be は、誰について話しているかによって形を変えます。これを活用（conjugation）と呼びます。現在形には3つの主な形があります：am、is、are です。am は自分自身に対してのみ使います。is は自分以外の1人の人や1つの物に使います。are はグループや、あなたが話しかけている相手に使います。これは天候に合わせて適切な服を選ぶようなものです。ビーチにパーカーは着ていきませんよね？ I is と言うのは、サハラ砂漠でスノーブーツを履くのと同じくらい奇妙に聞こえます。また、話すときはこれらの言葉を短縮するのが大好きです。そうすることで、より速く、より自然に聞こえます。I am と言う代わりに、I'm と言います。これはレースゲームのショートカットのような言語版です。
Formation Pattern
I には am を使います。（「自撮り」ルール）
I am a student. （短縮形：I'm）
he、she、it には is を使います。（「シングルフレンド」ルール）
He is tall. （短縮形：He's）
She is hungry. （短縮形：She's）
It is cold. （短縮形：It's）
you、we、they には are を使います。（「スクワッド」ルール）
You are funny. （短縮形：You're）
We are late. （短縮形：We're）
They are outside. （短縮形：They're）
I am a gamer. | 私はゲーマーです。 |
You are kind. | あなたは親切です。 |
He is a doctor. | 彼は医者です。 |
She is busy. | 彼女は忙しいです。 |
It is 10 PM. | 午後10時です。 |
We are ready. | 私たちは準備ができています。 |
They are fast. | 彼らは速いです。 |
When To Use It
to be を使います。- アイデンティティ: 誰かに自分の名前や職業を伝えるとき。
I am Alex.She is a developer. - 場所: Googleマップで自分がどこにいるか言うとき。
We are at the cafe.He is in London. - 特徴: 人や物を描写するとき。
The coffee is hot.You are very smart. - 感情: 今の気分を共有するとき。
I am excited!They are bored. - 状態・年齢: 人生に関する単純な事実。
It is Monday.I am 21 years old.
I am adventurous. I am a dog lover. My dog is very cute. と書くかもしれません。ほら、もうあなたはエキスパートです！「He is annoying.（彼はうざい）」と言いたいとき以外は、元カレを描写するのに使わないでくださいね。
Common Mistakes
I have 20 years.
I am 20 years old.
She very pretty.
She is very pretty.
- 「He」と「She」の混同: 性別代名詞に間違った形を使うのはよくあることです。覚えておいてください：男の子には
He、女の子にはSheです。弟をsheと呼ぶと、彼は混乱するかもしれませんが、少なくともあなたの文法は大丈夫です。 isとareの混同: グループであることを忘れて、よくThey isと言ってしまう人がいます。areは複数形のパーティーバスだと考えてください。- 短縮形の綴り:
You're（あなたは〜である）とYour（あなたのもの）を混同しないでください。これはインターネット上の議論の究極の火種です。これを正しく使えれば、TikTokのコメント欄で勝利できます。
Contrast With Similar Patterns
to be と一般動詞（動作を表す動詞）を混同します。特別な語尾を付けずにそれらをただくっつけることはできません。- To Be vs. 動作:
I am happy（描写）と言うことはできます。I run（動作）と言うこともできます。しかし、I am runと言うことはできません。それは、あなたが文字通り物理的な「走ること」そのものであるかのように聞こえます。それは非常に奇妙なスーパーパワーになってしまいます。 - To Be vs. To Have: 前述の通り、空腹や喉の渇きなどの感覚には
to beを使います。 ✗I have hunger.→ ✓I am hungry.物理的に所有しているものではなく、あなたの存在の状態を表すものにはto beを使ってください。 - 「It」の要素: 天気や時間には
It isを使います。日本語では単に「寒い」と言いますが、英語ではIt is cold.と言います。天気はそれ自体が一つのキャラクターなのです！
Quick FAQ
他の人に対して am を使えますか？
いいえ。am はわがままな動詞です。I としか付き合いません。
You are は常に複数形ですか？
いいえ！ You are は1人の人に対しても、グループに対しても使います。スイスアーミーナイフのように非常に用途が広いです。
なぜ I'm のような短縮形を使うのですか？
面んどくさがりだからです！冗談です。会話の流れが速くなり、WhatsAppのようなカジュアルな場面でより自然に聞こえるからです。
I am being a student と言えますか？
通常は言いません。I am a student は安定した事実です。I am being は、短期間だけ学生のように振る舞っていることを意味します。
ペットに is を使ってもいいですか？
はい！ペットがオスなら he、メスなら she を使ってください。わからない場合は it を使います。
年齢に to be は必要ですか？
はい、常に必要です！ I have 25 と言うと、英語のネイティブはあなたのバッグの中に25個のリンゴが入っていると思ってしまいます。
Present Simple Conjugation of 'To Be'
| Subject | Affirmative | Negative | Question |
|---|---|---|---|
|
I
|
am
|
am not
|
Am I?
|
|
You
|
are
|
are not / aren't
|
Are you?
|
|
He
|
is
|
is not / isn't
|
Is he?
|
|
She
|
is
|
is not / isn't
|
Is she?
|
|
It
|
is
|
is not / isn't
|
Is it?
|
|
We
|
are
|
are not / aren't
|
Are we?
|
|
They
|
are
|
are not / aren't
|
Are they?
|
Common Contractions
| Full Form | Contraction | Negative Contraction |
|---|---|---|
|
I am
|
I'm
|
I'm not
|
|
You are
|
You're
|
You aren't / You're not
|
|
He is
|
He's
|
He isn't / He's not
|
|
She is
|
She's
|
She isn't / She's not
|
|
It is
|
It's
|
It isn't / It's not
|
|
We are
|
We're
|
We aren't / We're not
|
|
They are
|
They're
|
They aren't / They're not
|
Meanings
The verb 'to be' describes the state, identity, or quality of a subject rather than an action.
Identity and Names
Used to state who or what someone or something is.
“I am Sarah.”
“This is a book.”
Location
Used to describe where someone or something is situated.
“He is at home.”
“The keys are on the table.”
Feelings and States
Used to describe emotions, physical conditions, or temporary states.
“I am hungry.”
“You are tired.”
Professions
Used to state a person's job or role.
“She is a teacher.”
“They are engineers.”
Age
Used to state how old someone or something is.
“I am twenty years old.”
“He is five.”
Reference Table
| 主語 (しゅご) | 「to be」動詞 (どうし) | 短縮形 (たんしゅくけい) | 例文 (れいぶん) |
|---|---|---|---|
|
I
|
am
|
I'm
|
I'm a student.
|
|
You (singular)
|
are
|
You're
|
You're smart.
|
|
He
|
is
|
He's
|
He's my brother.
|
|
She
|
is
|
She's
|
She's happy.
|
|
It
|
is
|
It's
|
It's cold.
|
|
We
|
are
|
We're
|
We're friends.
|
|
You (plural)
|
are
|
You're
|
You're all here.
|
|
They
|
are
|
They're
|
They're busy.
|
フォーマル度スペクトル
I am prepared to depart. (Leaving a location)
I am ready to go. (Leaving a location)
I'm ready! (Leaving a location)
I'm set. (Leaving a location)
「to be」の世界
識別
- I am a student 身元
- She is my friend 関係
説明
- It is cold 天気・状態
- They are happy 感情・状態
- He is tall 特徴
場所を示す
- We are at home 場所
- The book is on the table 位置
年齢・時間
- I am 20 years old 年齢
- It is 5 PM 時間
「to be」動詞の形：誰がどれを使う？
「Am」「Is」「Are」の選び方
主語は「I」ですか？
主語は単数形（he, she, it、または一人・一つのもの）ですか？
主語は「you」「we」「they」、または複数形（二人・二つ以上のもの）ですか？
「to be」動詞のよくある使い方
識別
- • I am a student.
- • She is my boss.
説明
- • He is tall.
- • The car is red.
場所
- • We are at home.
- • The keys are on the table.
感情・状態
- • They are happy.
- • I am tired.
年齢
- • He is 30 years old.
- • How old are you?
時間・日付
- • It is Monday.
- • It is 7 PM.
レベル別の例文
I am happy.
I am happy.
She is a doctor.
She is a doctor.
They are at school.
They are at school.
Are you cold?
Are you cold?
It is a big dog.
It is a big dog.
We are not hungry.
We are not hungry.
He's not from Italy.
He's not from Italy.
The keys aren't in my bag.
The keys aren't in my bag.
Is your mother a teacher?
Is your mother a teacher?
We're very tired after the trip.
We're very tired after the trip.
The weather is usually quite mild here.
The weather is usually quite mild here.
You are being very helpful today.
You are being very helpful today.
Is it true that she is moving?
Is it true that she is moving?
They are both interested in art.
They are both interested in art.
The results are to be announced tomorrow.
The results are to be announced tomorrow.
It is essential that he be informed.
It is essential that he be informed.
The building is currently being renovated.
The building is currently being renovated.
Whether that is the case remains to be seen.
Whether that is the case remains to be seen.
It was her who was responsible for the error.
It was her who was responsible for the error.
The truth is, I am quite exhausted.
The truth is, I am quite exhausted.
Were it not for your help, I would fail.
Were it not for your help, I would fail.
Such is the nature of the business.
Such is the nature of the business.
To be, or not to be, that is the question.
To be, or not to be, that is the question.
The problem is not so much that he is poor, but that he is lazy.
The problem is not so much that he is poor, but that he is lazy.
There is no denying the impact of his work.
There is no denying the impact of his work.
The city is but a shadow of its former self.
The city is but a shadow of its former self.
間違えやすい
Many languages use 'have' for age, hunger, and thirst.
Learners use 'It is' to mean 'exists'.
Learners try to contract 'Yes, I am' to 'Yes, I'm'.
よくある間違い
I is happy.
I am happy.
She teacher.
She is a teacher.
I have 20 years old.
I am 20 years old.
They no are here.
They are not here.
Do you be tired?
Are you tired?
Yes, I'm.
Yes, I am.
Is the cats hungry?
Are the cats hungry?
I am being a student.
I am a student.
It's mean that...
It means that...
If I was you...
If I were you...
文型パターン
I am ___.
She is not ___.
Are they ___?
It is ___ today.
Real World Usage
I'm a photographer based in NYC.
Are you here yet?
I am very interested in this role.
Where is gate 5?
I am sick.
Is this dish spicy?
主語とセットで練習しよう！
「to be」動詞を忘れないで！
短縮形を使いこなそう！
They make your English sound more natural and fluent!
「How are you?」は超定番の挨拶！
How are you?耳で覚えてみよう！
Listen for the Sound
Smart Tips
Always use 'I'm' followed by your name. It sounds much more natural than 'My name is...'.
Use the full form in positive short answers to avoid sounding unfinished.
Always start with 'It's'. English always needs a subject, even for weather.
Always use 'are', even if you are talking to just one person.
発音
Contraction Reduction
In fast speech, 'I am' becomes 'I'm' /aɪm/. 'You are' becomes 'You're' /jʊər/.
The 's' sound in 'is'
The 's' in 'is' and 'He's' sounds like a /z/.
Linking 'are'
When 'are' is followed by a vowel, the 'r' is often pronounced clearly (e.g., 'They are at...').
Yes/No Question Rising
Are you happy? ↗
Asking for confirmation.
Statement Falling
I am happy. ↘
Giving information.
暗記しよう
記憶術
Remember 'A-I-R': Am for I, Is for Singular, Are for Rest.
視覚的連想
Imagine a bridge with three lanes. The first lane is only for a single person named 'I' (Am). The second lane is for single cars (Is). The third lane is for buses with many people (Are).
Rhyme
I am, you are, he is too. We are, they are, how are you?
Story
Once there was a king named 'I' who only liked the word 'Am'. His three children, He, She, and It, shared a small toy called 'Is'. All the other people in the kingdom (You, We, They) had to share a big boat called 'Are'.
Word Web
チャレンジ
Look around the room and say 5 sentences using 'is' or 'are' to describe what you see (e.g., 'The lamp is on').
文化メモ
Americans use 'I'm good' to mean 'I am fine' or 'No thank you'.
In some dialects, 'I'm' is used even in places where Americans might use the full 'I am'.
The 'invariant be' is used for habitual actions, while the copula is sometimes omitted for present states.
The English verb 'to be' is a 'suppletive' verb, meaning it comes from three different Proto-Indo-European roots.
会話のきっかけ
Where are you from?
What is your job?
How are you feeling today?
Who is your favorite celebrity?
日記のテーマ
よくある間違い
Test Yourself
My sister ___ a doctor.
Find and fix the mistake:
You is very kind.
Arrange the words in the correct order:
All words placed
Click words above to build the sentence
Score: /3
練習問題
8 exercisesShe ___ a very kind person.
Which one is correct?
Find and fix the mistake:
I'm not have hungry.
you / from / Are / London / ?
I -> ?, He -> ?, We -> ?
___ (It is) very hot today.
We ___ ready.
Are you a student? Yes, I ___.
Score: /8
Practice Bank
12 exercisesThe weather today ___ sunny.
I ___ from Canada.
正しい文章を選びましょう:
She not is ready.
英語に翻訳しましょう: 'El libro está en la mesa.'
これらの単語を並べ替えて質問を作りましょう:
主語と正しい形を合わせましょう:
My friends is very busy this week.
英語に翻訳しましょう: 'Ella no está aquí ahora.'
How old ___ your brother?
正しい文章を選びましょう:
これらの単語を並べ替えて文章を作りましょう:
Score: /12
よくある質問 (8)
English is an old language, and the verb 'to be' comes from different roots. It's irregular, so you just have to memorize these specific pairs.
No, in formal writing, you should use the full forms like `I am` or `It is`. Contractions are for speaking and casual writing.
There is no difference in meaning. `Isn't` is just the shorter, more common way to say it in conversation.
In English, age is considered a state of being (who you are), not a possession (something you have).
Both! In English, `you` is used for one person and for a group of people. The verb is always `are` for both.
Only with the subject `I`. It is the most exclusive form of the verb.
Yes, but that's for more advanced tenses like the Present Continuous (e.g., 'I am running'). For now, focus on using it with nouns and adjectives.
Usually, yes. But it can also mean 'It has' in the present perfect (e.g., 'It's been a long day'). Context will tell you which one it is!
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
Ser / Estar
English doesn't distinguish between permanent and temporary 'being'.
Être
French uses 'to have' for physical states like hunger.
Sein
German word order changes more than English in questions.
Desu / Arimasu / Imasu
Japanese verbs don't change based on 'I', 'You', or 'They'.
Zero Copula
Arabic omits the verb entirely in the present affirmative.
Shì (是)
Chinese doesn't use 'to be' with adjectives.
Learning Path
Prerequisites
Continue With
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