Grammar Rule in 30 Seconds
Use 'can' plus a base verb to show what you are able to do right now.
- No 's' for he/she/it: 'He can swim', not 'He cans swim'.
- Never use 'to' after can: 'I can dance', not 'I can to dance'.
- Negative is 'cannot' or 'can't': 'They can't come today'.
Overview
can です。can が魔法の言葉なのか。それは、この一言を覚えるだけで、あなたの「できること」や「可能性」を世界中の人に伝えられるようになるからです。自己紹介で「ピアノが弾けます」と言ったり、仕事の面接で「英語が話せます」とアピールしたり、あるいは友達に「今日会える？」と聞いたり……。can は、日常会話のあらゆる場面で主役になる言葉です。modal verbs（助動詞）というグループがあります。これは、動詞（アクションを表す言葉）に特定の「意味のスパイス」を加える役割を持っています。今回学習する can は、その中でも「現在の能力（Present Ability）」を表す最も基本的な助動詞です。can という言葉は、実は英語のルールの中でも驚くほどシンプルで、覚えやすい特徴を持っています。日本語の「〜ができる」「〜（ら）れる」という表現と比べながら、その使いこなし方を丁寧に見ていきましょう。このレッスンが終わる頃には、あなたも自信を持って I can... と言えるようになっているはずです！can が英語の文章の中でどのような役割を果たしているのか、その仕組みを理解しましょう。日本語と英語の構造的な違いに注目すると、より深く理解できます。SVO（主語＋動詞＋目的語）の言語です。能力を表す can は、必ず 「主語」と「動詞」の間 に割り込みます。- 日本語: 私は ＋ 泳ぐ ＋ ことができる。
- 英語:
I(私は) ＋can(できる) ＋swim(泳ぐ)。
can の「不変」のルールHe や She（三人称単数）になると s をつけたり、形を変えたりする必要がありますよね。しかし、can は どんな主語が来ても形が一切変わりません。I can(私はできる)You can(あなたはできる)He can(彼はできる) ←He cansとは言いません！They can(彼らはできる)
can の後ろに来る動詞は、常に 「原形（Base Form）」 です。原形とは、辞書に載っているそのままの形のこと。s をつけたり、ing にしたり、過去形にしたりする必要はありません。can という強力な言葉が前にいるので、後ろの動詞はリラックスして元の姿のままでいられる、とイメージしてみてください。can + [動詞の原形]I | can | speak | English. |You | can | cook | Japanese food. |He | can | drive | a car. |My cat | can | jump | very high. |We | can | play | the piano. |I can speak English.（私は英語が話せます。）She can run very fast.（彼女はとても速く走れます。）This smartphone can take beautiful photos.（このスマホは綺麗な写真が撮れます。）
can の後ろに not を置きます。通常、短縮形の can't が日常会話では最もよく使われます。can't (または cannot) + [動詞の原形]I can't swim.（私は泳げません。）He can't come to the party.（彼はパーティーに来られません。）They cannot understand Japanese.（彼らは日本語を理解できません。）
cannot は一つの単語として綴ります。これはフォーマルな文書や、強調したい時に使われます。普段の LINE や会話では can't で十分です。can を文の先頭に持っていきます。主語と can の位置を入れ替える（倒置）だけです。Can + [主語] + [動詞の原形] ?Can you play the guitar?（ギターは弾けますか？）Can he speak French?（彼はフランス語を話せますか？）Can we park here?（ここに駐車できますか？）
Yes, I can./No, I can't.Yes, she can./No, she can't.
can を使うタイミングは、大きく分けて3つのシチュエーションがあります。日本語の感覚と照らし合わせながら確認しましょう。I can use Excel and PowerPoint.（エクセルとパワーポイントが使えます。）My sister can speak three languages.（姉は3ヶ国語を話せます。）He can play the violin.（彼はバイオリンが弾けます。）
Birds can fly, but penguins can't.（鳥は飛べますが、ペンギンは飛べません。）I can see the mountains from my window.（窓から山が見えます。）Can you hear me?（私の声が聞こえますか？ ※電話やオンライン会議でよく使います）
I can meet you at 5 PM.（5時にあなたに会えます＝会う時間が取れます。）We can buy tickets online.（チケットはオンラインで買えます＝買う方法があります。）You can find a convenience store everywhere in Tokyo.（東京ではどこでもコンビニを見つけられます。）
can の後に to を入れてしまう- 間違い:
I can to swim. - 正しい:
I can swim.
want to（〜したい）や need to（〜する必要がある）などの形を先に学ぶことが多いため、動詞を繋ぐときには to が必要だという思い込みが生じがちです。しかし、can は助動詞。助動詞の直後は必ず「動詞の原形」のみです。to は不要な「壁」になってしまうので、取り除きましょう。s をつけてしまう- 間違い:
He cans play soccer. - 正しい:
He can play soccer.
He/She/It なら動詞に s」を熱心に勉強した人ほど、このミスをします。しかし、前述の通り can は不変の魔法の言葉です。主語が誰であっても can は can のまま。これほど楽なルールはありません！- 間違い:
Can speak English. - 正しい:
I can speak English.
can を使うときは、誰の能力なのかをはっきりさせるために、必ず I や You などの主語から始めてください。can と似た意味を持つ表現との違いを整理しておきましょう。特に A1 レベルで混乱しやすいのが know how to との使い分けです。can | 最も一般的。潜在的な能力や今の可能性を広くカバーする。 | I can swim. (私は泳げる能力がある) |know how to | 「やり方を知っている」という知識や技術面にフォーカスする。 | I know how to swim. (泳ぎ方を知っている) |be able to | can よりも少しフォーマル、または一時的な能力を指すことが多い。 | I am able to finish it. (それを終わらせることができます) |can を完璧に使いこなせるようになりましょう。know how to は「（習い事などで）やり方を習得した」というニュアンスを強調したい時に使います。例えば、I can use a computer. と I know how to use this software. では、後者の方がより具体的な操作方法に精通している感じが出ます。can't と cannot はどう使い分ければいいですか？can't を使います。cannot は、公的な書類や、あるいは「絶対にダメ！」と強調したい時に使われます。まずは can't をスムーズに発音できるように練習しましょう。can の発音が「キャン」なのか「クン」なのか分かりません。I can swim. の can は、実はあまり強く発音されず「クン」に近い音になります。逆に、否定文の I can't swim. の can't は「キャント（またはキャン）」とはっきり強く発音されます。相手に「できる」のか「できない」のかを伝える際、この強調の差が重要になります。Can I...? は「〜してもいいですか？」という許可の意味になりますか？can は「〜してもいい？」という軽い許可を求める時にも非常によく使われます。例えば Can I use your pen?（ペン借りてもいい？）などです。これも「そうする可能性がある（できる）」という根っこは同じ意味から来ています。can はあくまで「主語が〜する能力がある」という能動的な意味が基本です。日本語の「このキノコは食べられる（食用だ）」のような場合は、This mushroom can be eaten. のように形が変わりますが、A1レベルではまず I can eat...（私は〜を食べられる）という「自分の能力」からマスターしていけば大丈夫ですよ！can は、あなたの世界を広げるための第一歩です。今日から、身の回りにある「できること」を英語で探してみてください。I can drink coffee. I can go to the station. そんな簡単なことからでいいのです。頑張るあなたの英語学習を、いつも応援しています！2. Negative Contractions
| Full Form | Contraction | Usage |
|---|---|---|
|
cannot
|
can't
|
Most common in speech
|
|
can not
|
n/a
|
Rare, used for emphasis
|
Conjugation of 'Can' (Present Ability)
| Subject | Modal Verb | Base Verb | Example |
|---|---|---|---|
|
I
|
can
|
swim
|
I can swim.
|
|
You
|
can
|
dance
|
You can dance.
|
|
He / She / It
|
can
|
sing
|
She can sing.
|
|
We
|
can
|
cook
|
We can cook.
|
|
They
|
can
|
run
|
They can run.
|
Meanings
The word 'can' is a modal verb used to express that someone has the physical power, knowledge, or skill to perform an action in the present.
Physical Ability
Having the physical strength or capacity to do something.
“She can run a marathon in under four hours.”
“He can lift heavy boxes easily.”
Learned Skill
Knowing how to do something because you studied or practiced it.
“Can you play the piano?”
“My brother can code in Python.”
General Possibility
Expressing that something is possible or allowed by circumstances.
“You can see the mountains from my window.”
“It can get very cold here in winter.”
Reference Table
| タイプ | 構造 | 例 | 短い返事 |
|---|---|---|---|
|
Positive
|
Subject + can + Base Verb
|
I can speak English.
|
N/A
|
|
Negative (formal)
|
Subject + cannot + Base Verb
|
He cannot swim.
|
N/A
|
|
Negative (informal)
|
Subject + can't + Base Verb
|
We can't go.
|
N/A
|
|
Question
|
Can + Subject + Base Verb?
|
Can you help me?
|
Yes, I can. / No, I can't.
|
|
Question
|
Can + Subject + Base Verb?
|
Can she drive?
|
Yes, she can. / No, she can't.
|
フォーマル度スペクトル
I wonder if you could possibly assist me? (Requesting assistance)
Can you help me, please? (Requesting assistance)
Can you give me a hand? (Requesting assistance)
Yo, can you help a bro out? (Requesting assistance)
「Can」（能力）を理解しよう
構造
- 肯定文 Subject + can + Base Verb
- 否定文 Subject + cannot / can't + Base Verb
- 疑問文 Can + Subject + Base Verb?
ポイント
- 「to」は不要 Never 'can to verb'
- 「-s」は不要 Never 'cans' for he/she/it
- 「do」は不要 For questions or negatives
使い方
- スキル I can play guitar.
- 身体能力 She can run fast.
- 知的能力 He can remember names.
「Can」（能力）とよくある間違いを比べよう
「Can」の活用術：能力表現の簡単ガイド
能力やスキルを表現したいですか？
肯定文ですか？
否定文ですか？
質問文ですか？
あなたは何ができますか？
スキル
- • I can speak English.
- • She can draw.
- • We can play chess.
身体能力
- • He can run fast.
- • They can lift heavy boxes.
- • I can touch my toes.
感覚的な能力
- • Can you see that?
- • I can hear the music.
- • She can smell dinner.
できないこと
- • I can't sing.
- • He cannot drive.
- • We can't find it.
レベル別の例文
I can swim.
I am able to swim.
She can't cook.
She is not able to cook.
Can you help me?
Are you able to help me?
They can speak English.
They know how to speak English.
He can play the guitar very well.
He has the skill to play guitar.
We can't come to the party tonight.
It is not possible for us to come.
Can she drive a car?
Does she have the skill to drive?
You can find the keys in the drawer.
It is possible to find them there.
I can usually finish my work by 5 PM.
It is generally possible for me.
Can you tell me where the bank is?
Are you able to provide directions?
It can be quite expensive to live in London.
It is a general truth/possibility.
I can't believe he said that!
I find it impossible to believe.
The new engine can reach speeds of 200mph.
The engine has the capacity.
You can't have seen him; he's in New York.
It is logically impossible.
Can I just say how much I appreciate this?
Seeking permission to speak.
Learning a language can be a lifelong journey.
It has the potential to be.
One can hardly expect them to agree immediately.
It is not reasonable to expect.
The implications can be seen across the entire sector.
The effects are visible.
I can't help but feel we've missed something.
I am unable to avoid this feeling.
Can we not simply admit that we were wrong?
A rhetorical suggestion.
The sheer scale of the project can scarcely be imagined.
It is almost impossible to imagine.
Such behavior can, and often does, lead to dismissal.
It has the inherent potential.
Can it be that the legends are actually true?
A poetic or archaic inquiry.
The virus can remain dormant for several years.
Biological capacity.
間違えやすい
Learners use 'can' for permission when 'may' is traditionally required.
Using 'can' for past abilities.
Learners wonder if they are different.
よくある間違い
I can to swim.
I can swim.
He cans play soccer.
He can play soccer.
I no can go.
I can't go.
Do you can help?
Can you help?
I can't to hear you.
I can't hear you.
She can sings.
She can sing.
I am can swim.
I can swim.
I will can go tomorrow.
I will be able to go tomorrow.
I have could do it.
I have been able to do it.
He can speaks English.
He can speak English.
It can't have been him, can it?
Correct as is, but learners often use 'couldn't' incorrectly here.
文型パターン
I can ___.
Can you ___?
He/She can't ___ very well.
Where can I ___?
Real World Usage
I can speak three languages fluently.
Can you lift this weight?
Where can I buy a bus ticket?
I can't believe I just won the lottery!
The app can't open the file.
Can you chop the onions?
「To」はつけない！
「Can」に「-s」は不要！
短縮形を使いこなそう！
「Can」で丁寧な依頼も！
Smart Tips
Use 'can' to list your skills clearly and concisely.
Immediately delete the 'to'. Modal verbs are 'to-free' zones.
Start with 'Can you...' to sound helpful and friendly.
Use the contraction 'can't' instead of 'cannot' in 99% of conversations.
発音
The Weak 'Can'
In affirmative sentences, 'can' is usually unstressed and sounds like /kən/ (kun).
The Strong 'Can't'
In negative sentences, 'can't' is stressed and the vowel is longer /kænt/.
The Glottal Stop
In American English, the 't' in 'can't' is often not fully pronounced, replaced by a sharp stop in the throat.
Question Rise
Can you swim? ↗
Standard yes/no question intonation.
暗記しよう
記憶術
C.A.N. = Capability Always Now.
視覚的連想
Imagine a 'Can' of soda with a muscle arm growing out of it. The muscle represents the 'ability' or 'power' to do something.
Rhyme
With 'can' the verb is always bare, no 's' or 'to' should ever be there!
Story
Meet 'Can-do Ken.' Ken is a superhero. He can fly, he can jump, and he can speak every language. But Ken is simple—he never uses 'to' and he never adds an 's' to his name, even when his friend 'She' is with him.
Word Web
チャレンジ
Look around your room. Find 5 things you can do with the objects you see (e.g., 'I can read this book', 'I can open this window').
文化メモ
Using 'can' for permission (e.g., 'Can I go?') is very common, though teachers might say 'May I go?' is more 'correct'.
In professional settings, 'can' is used to show confidence in one's skills.
Often use 'can't' with a very broad 'ah' sound /kɑːnt/.
From the Old English 'cunnan', meaning 'to know' or 'to have mental power'.
会話のきっかけ
What is one thing you can do very well?
Can you speak any other languages?
What can people do for fun in your city?
Can you play any musical instruments?
日記のテーマ
よくある間違い
Test Yourself
My little sister ___ read yet.
Can'tは「cannot」の短縮形で、「できない」という能力の欠如を表します。「No can」は間違いで、「cannot to」は「to」が不必要です。Find and fix the mistake:
He cans play the piano well.
Canはどの主語に対しても「-s」をつけません。正しい形は「can」です。Choose the correct sentence:
Score: /3
練習問題
8 exercisesWhich sentence is correct?
I ___ speak Chinese, but I want to learn it one day.
Find and fix the mistake:
Do you can help me with my homework?
piano / she / play / can / the / ?
Can they swim?
I ___ see the stars tonight.
My cat ___ jump very high.
___ I borrow your pen?
Score: /8
Practice Bank
12 exercisesI ___ see the stage from here.
My phone is broken; I ___ call anyone.
She can to swim very well.
Do you can speak French?
Choose the correct sentence:
Choose the correct sentence:
Translate into English: 'Ella no puede cocinar.'
Translate into English: '¿Puedes ayudarme?'
Arrange these words into a sentence:
Arrange these words into a question:
Match the subjects with the correct form:
Match the subjects with their negative 'can' form:
Score: /12
よくある質問 (8)
Yes, they mean the same thing. `can't` is a contraction and is very common in speaking. `cannot` is more formal and is always written as one word.
Not directly. We usually use `be able to` for the future (e.g., 'I will be able to come'). However, for scheduled events, we sometimes use `can` (e.g., 'I can meet you tomorrow').
Because `can` is a modal verb. Modal verbs are special and never change their form, no matter who the subject is.
They are very similar. `can` is more general and covers physical ability, while `know how to` specifically refers to learned skills. 'I can breathe' (physical) vs 'I know how to drive' (skill).
It is almost always written as one word: `cannot`. You only see `can not` if the 'not' belongs to a different part of the sentence, which is very rare.
Yes! In modern English, 'Can I...?' is perfectly acceptable for permission, though 'May I...?' is more formal.
Focus on the vowel. In `can`, the vowel is short and weak. In `can't`, the vowel is stronger and longer. In American English, the 't' is often a 'stop' in the throat.
No. You cannot put two modal verbs together. Instead of 'will can', you must say `will be able to`.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
Poder
English 'can' does not conjugate for person.
Pouvoir
French distinguishes between 'pouvoir' (possibility) and 'savoir' (learned skill).
Können
Word order: English keeps 'can' and the verb together.
~eru / ~rareru
Japanese uses a suffix; English uses a separate modal verb.
Yastati'a (يستطيع)
Arabic 'can' conjugates for gender and number.
Hui (会) / Neng (能)
Chinese has two different words depending on the type of ability.
Learning Path
Prerequisites
Continue With
関連動画
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