Grammar Rule in 30 Seconds
Use 'If + Present Simple' and 'Can + Verb' to talk about future things that are possible or allowed.
- The 'if' part uses Present Simple: 'If it rains...'
- The result part uses 'can' + base verb: '...we can stay home.'
- Use 'can' instead of 'will' to show ability or permission, not just certainty.
Overview
will（起こる）」かだけを話しているのではありません。「何がcan（起こり得る）」かを話しているのです。このwillからcanへの微妙な変化により、雰囲気が「確実な結果」から「可能性、許可、そして新しいスキルの世界」へと変わります。「パーティーに行くことになるよ（You will go）」（命令または予測）と、「パーティーに行けるよ（You can go）」（待ち望んでいた許可）の違いです。How This Grammar Works
canを使った第1条件文は、許可、機会、または能力を伴う現実の出来事について話すための頼れるツールです。科学的な確信や固い約束のように感じられる標準的なwillバージョンとは異なり、canバージョンははるかに柔軟です。これは、条件の結果が単なる将来の出来事ではなく、将来の「選択肢」である場合に使用されます。取引をしたり、アドバイスをしたり、アプリの使い方を説明したりするのに最適です。「もしXをすれば、Yがあなたの選択肢になる」ということです。これは究極の「自分自身の冒険を選ぼう」文法パターンです。ただ、猫に何をすべきか教えるためにこれを使わないでください。彼らはどうせ条件も結果も無視しますから。
Formation Pattern
ifの部分）：ifの後に現在形（Present Simple）を使います。未来のことについて話していても、動詞は現在のままにします。
canの部分）：canの後に動詞の原形（Base Form）を使います（toも-ingも-edも付けません）。
If + [主語] + [現在形の動詞], [主語] + can + [動詞の原形].
If you pass the test, you can borrow my car.（テストに合格したら、私の車を借りてもいいよ）
canの部分が最初に来る場合、コンマは必要ありません。
can borrow my car if you pass the test.（テストに合格すれば、私の車を借りることができるよ）
ifで文が始まるなら、段差が必要です。ifが真ん中にあるなら、それが接着剤の役割を果たすので、段差は必要ありません。単純なルールですが、コンマを忘れると、どこかの文法教師が卒倒するかもしれません。
When To Use It
canが輝く4つの大きな場面を紹介します。- 許可を与える： これが最大の用途です。「家事を終えたら、ヴァロラント（Valorant）をプレイしてもいいよ」。ここではあなたがボスです。条件は、許可を得るために彼らが支払う代償です。
- 能力を表現する： 「翻訳者が見つかれば、メニューを理解できる」。これは許可ではなく、その行動が物理的または精神的に可能かどうかについてです。
- 選択肢を提示する： 「お腹が空いているなら、寿司を注文できるよ」。必ず注文すると言っているのではなく、実行可能な選択肢として提示しています。丁寧で、プレッシャーを与えません。
- ルールやシステムを説明する： 「学生証があれば、割引を受けられます」。これは世の中の仕組みを説明しています。アプリやウェブサイト、役所の論理です。
canを使うと、親切で柔軟な印象を与えます。条件文ファミリーの「クールな兄貴分」のような存在です。
Common Mistakes
- 1「Will」の罠： 多くの人が
if節にwillを入れようとします。If I will see him, I can tell him.ダメです。 今すぐやめてください。if節は常に現在形です。If I see him, I can tell him. - 2「To」への執着：
canの後にtoを置かないでください。If it rains, we can to stay home.痛恨のミスです。 単にcan stayです。canゾーンにtoは立ち入り禁止です。 - 3三人称単数のS：
if節で、he/she/itに対するsを忘れないでください。If she go, she can see.間違いです。If she goes, she can see.しかし、canの後の動詞にsを付けてはいけません。She can goesは文法上の犯罪です。 - 4コンマのドラマ： 前述の通り、
Ifで始める場合はコンマを使ってください。そうしないと、読者は頭の中で文を読みながら息切れしてしまいます。
Contrast With Similar Patterns
willやcouldではなく、いつcanを使うべきか、どうやって見分ければいいでしょうか？- Can vs Will： 確定的な結果には
willを使います。If you jump, you will fall.（重力は非情です）。可能性や許可にはcanを使います。If you jump, you can win the prize.（飛ばないかもしれませんが、選択肢はあります）。 - Can vs Could： これは現実味の問題です。
canは第1条件文（現実的な可能性）に使います。If I have money, I can buy it.（すぐにお金が手に入るかもしれない）。couldは第2条件文（想像上／可能性が低い）に使います。If I had a billion dollars, I could buy an island.（10億ドルなんて持っていないし、今はカップラーメンを食べています）。 - Can vs May： どちらも許可に使えますが、現代の日常英会話では
canの方がはるかに一般的です。mayはシルクハットと片眼鏡を身につけているような響きがあります。非常に格式高いZoom会議でない限り、canで通しましょう。
Quick FAQ
これらの文で can't を使えますか？
もちろんです！ If you don't have a ticket, you can't enter. 否定的な結果についても、全く同じように機能します。
質問したい場合はどうすればいいですか？
主節を入れ替えるだけです。 If I finish early, can I leave? または Can I leave if I finish early?
if の代わりに他の単語を使えますか？
はい！ when、as soon as、unless はすべて同じパターンで機能します。 Unless you pay, you can't watch. （注：unless は if not の意味です）。
ビジネスメールでこれを使っても大丈夫ですか？
はい、非常に一般的です。 If you are available on Tuesday, we can discuss the project. プロフェッショナルでありながら協調的な印象を与えます。
can は常に許可を意味しますか？
常にではありません。単に「可能性がある」ことを意味する場合もあります。文脈がすべてです！ 上司と話しているなら許可ですし、天気について話しているなら可能性です。
Structure of First Conditional with 'Can'
| Clause Type | Grammar Structure | Example |
|---|---|---|
|
Condition (If-Clause)
|
If + Subject + Present Simple
|
If you study hard,
|
|
Result (Main Clause)
|
Subject + Can + Base Verb
|
you can pass the exam.
|
|
Negative Result
|
Subject + Cannot (Can't) + Base Verb
|
you can't go out.
|
|
Question Form
|
Can + Subject + Base Verb + If...?
|
Can we go if it stops raining?
|
Contractions in the Result Clause
| Full Form | Contraction | Usage Note |
|---|---|---|
|
cannot
|
can't
|
Most common in speech and informal writing.
|
|
can not
|
N/A
|
Rarely written as two words unless for extreme emphasis.
|
Meanings
A structure used to express that a future outcome is possible (ability) or permitted (permission) only if a specific condition happens first.
Future Ability
Expressing that someone will have the skill or opportunity to do something if a condition is met.
“If I find my glasses, I can read the map.”
“If we save enough money, we can buy a new car next year.”
Future Permission
Expressing that someone will be allowed to do something if they fulfill a requirement.
“If you eat your vegetables, you can have dessert.”
“If she passes the test, she can borrow my car.”
Theoretical Possibility
Suggesting a potential option among many if a situation occurs.
“If the hotel is full, we can sleep in the van.”
“If you are lost, you can call me anytime.”
Reference Table
| 状況の種類 | If節 (条件) | 主節 (結果) | 強調点 |
|---|---|---|---|
|
能力・機会
|
If you study hard
|
you can pass the exam
|
能力
|
|
許可
|
If you finish your chores
|
you can watch TV
|
許可
|
|
否定的な能力
|
If it snows heavily
|
we can't drive
|
能力不足
|
|
否定的な許可
|
If you don't have a ticket
|
you can't enter
|
禁止
|
|
質問 (許可)
|
If I finish early
|
can I leave?
|
許可を求める
|
|
質問 (能力)
|
If it's sunny
|
can we go hiking?
|
可能性を尋ねる
|
フォーマル度スペクトル
If your tasks are completed, you can depart for the day. (Workplace)
If you finish your work, you can go home. (Workplace)
If you're done, you can head out. (Workplace)
If you're through, you can bail. (Workplace)
仮定法第一文型 with 'Can' の解説
構造
- If + Simple Present 条件節
- Subject + Can + Base Verb 主節
主な意味
- Ability 〜する能力がある
- Permission 〜する許可がある
- Opportunity 〜する機会がある
主要な例文
- If it rains, we can stay inside. 能力
- You can go if you finish. 許可
仮定法第一文型における 'Can' vs. 'Will'
仮定法第一文型で 'Can' を使うかどうかの判断
その状況は現実的で、起こりそうな未来の出来事ですか？
結果として、能力、許可、または機会を表現したいですか？
'if' 節は現在形ですか？
条件文における 'Can' の日常的な使い方
計画
- • If it's sunny, we can go to the park.
- • If you finish early, we can get coffee.
交渉
- • If you help me, I can finish faster.
- • You can borrow my car if you fill the tank.
許可を求めたり与えたりする
- • If I finish, can I leave?
- • You can watch TV if your homework is done.
能力を述べる
- • If I practice, I can improve.
- • If the system upgrades, it can handle more data.
レベル別の例文
If I see him, I can say hello.
If I see him, I can say hello.
If you are hungry, you can eat an apple.
If you are hungry, you can eat an apple.
If it is sunny, we can go to the park.
If it is sunny, we can go to the park.
If you have a pen, I can write the name.
If you have a pen, I can write the name.
If you don't hurry, you can't catch the bus.
If you don't hurry, you can't catch the bus.
If she likes the dress, she can buy it.
If she likes the dress, she can buy it.
If we have a map, we can find the museum.
If we have a map, we can find the museum.
Can I watch TV if I finish my homework?
Can I watch TV if I finish my homework?
If you book the tickets now, you can get a discount.
If you book the tickets now, you can get a discount.
If the Wi-Fi is slow, you can use the Ethernet cable.
If the Wi-Fi is slow, you can use the Ethernet cable.
We can go for a coffee if you have twenty minutes.
We can go for a coffee if you have twenty minutes.
If he doesn't feel better, he can't join the meeting.
If he doesn't feel better, he can't join the meeting.
If you provide a valid ID, you can access the building after hours.
If you provide a valid ID, you can access the building after hours.
If the company expands, we can hire more staff in the autumn.
If the company expands, we can hire more staff in the autumn.
You can't expect to improve if you don't practice consistently.
You can't expect to improve if you don't practice consistently.
If the software crashes, you can always restore the previous version.
If the software crashes, you can always restore the previous version.
If the negotiations stall, we can explore alternative suppliers.
If the negotiations stall, we can explore alternative suppliers.
If you look closely at the data, you can see a clear trend emerging.
If you look closely at the data, you can see a clear trend emerging.
If the government intervenes, they can stabilize the currency.
If the government intervenes, they can stabilize the currency.
We can hardly blame him if he decides to resign under these conditions.
We can hardly blame him if he decides to resign under these conditions.
If we concede this point, we can effectively dismantle their entire argument.
If we concede this point, we can effectively dismantle their entire argument.
If the market remains volatile, one can only speculate as to the long-term fallout.
If the market remains volatile, one can only speculate as to the long-term fallout.
If the author intended to provoke, she can certainly claim success.
If the author intended to provoke, she can certainly claim success.
If we are to succeed, we can afford no further delays.
If we are to succeed, we can afford no further delays.
間違えやすい
Learners mix up 'If I have time, I can help' (likely) with 'If I had time, I could help' (unlikely).
Learners use 'will' when they mean 'permission' or 'ability'.
Using 'if' for things that are 100% certain to happen.
よくある間違い
If I will see him, I can tell him.
If I see him, I can tell him.
If it rains, we will can't go.
If it rains, we can't go.
If he come, he can help.
If he comes, he can help.
If you are happy, you can to dance.
If you are happy, you can dance.
If you can help me, I will be happy.
If you help me, I can be happy.
We can go if it will be sunny.
We can go if it is sunny.
If she study, she can pass.
If she studies, she can pass.
If the weather is good, we will can go hiking.
If the weather is good, we can go hiking.
If I would have time, I can help.
If I have time, I can help.
If you'll finish early, you can go.
If you finish early, you can go.
文型パターン
If you ___, you can ___.
We can ___ if the ___ is ___.
If ___ doesn't ___, we can't ___.
Can I ___ if I ___?
Real World Usage
If u r free later, we can grab food.
If you join our team, you can expect a great benefits package.
If I pay extra, can I get double cheese?
If your bag is overweight, you can pay the fee at the counter.
If you tidy your toys, you can watch a cartoon.
If the light is red, you can try restarting the router.
現実的な可能性を見極めよう
「will can」の落とし穴に注意
許可と能力を明確に
状況がカギ
コンマのルールも大切
Smart Tips
Just use 'can'. It's shorter, more natural, and means the same thing in a first conditional.
Use 'can' to show that the result is an option, not a requirement.
Stop! Check if the 'will' is right after 'if'. If it is, delete it.
Start the sentence with 'Can I...' to make it a question.
発音
The Weak 'Can'
In affirmative sentences, 'can' is usually unstressed and sounds like /kən/.
The Strong 'Can't'
In negative sentences, 'can't' is stressed and the vowel is clearer /kænt/ (US) or /kɑːnt/ (UK).
Rising-Falling
If it rains (rising), we can stay home (falling).
The rising tone on the if-clause shows the condition is pending; the falling tone on the result shows the conclusion.
暗記しよう
記憶術
If the Present is the Key, then 'Can' is the Door you open.
視覚的連想
Imagine a gate with a sign that says 'IF'. Once you walk through the gate (the condition), you find a toolbox labeled 'CAN'. You can now use any tool inside.
Rhyme
If the first part is in the now, 'Can' will show you how!
Story
A boy wants to play video games. His mom says, 'If you clean your room, you can play.' He cleans (Present Simple), and suddenly the console turns on (Ability/Permission).
Word Web
チャレンジ
Write 3 things you can do this weekend if the weather is good.
文化メモ
British speakers often use 'can' in conditionals to be polite and indirect, especially when offering help. 'If you're struggling, I can give you a hand.'
In US business culture, 'can' is used in conditionals to emphasize 'can-do' attitude and problem-solving. 'If we hit a snag, we can pivot quickly.'
Australians frequently use 'can' in conditionals with 'reckon' to express a likely possibility. 'If it's hot, I reckon we can go for a swim.'
The word 'if' comes from Old English 'gif', and 'can' comes from 'cunnan' (to know how to).
会話のきっかけ
What can you do if it rains this weekend?
If you win the lottery, what can you buy for your family?
If you have a free week, where can you travel?
If your boss offers you a promotion in another country, can you accept it?
日記のテーマ
よくある間違い
Test Yourself
If you study hard, you ___ pass the exam.
Find and fix the mistake:
If it will rain tomorrow, we can stay inside.
Arrange the words in the correct order:
All words placed
Click words above to build the sentence
Score: /3
練習問題
8 exercisesIf she ___ (have) enough money, she ___ (can/buy) the car.
Choose the correct sentence:
Find and fix the mistake:
If you can to help me, I can finish early.
can / if / you / go / finish / you
Si tienes tiempo, puedes llamarme.
1. If it's hot... / 2. If you're tired... / 3. If you're lost...
Can I borrow your bike?
If we don't have a key, we ___ enter.
Score: /8
Practice Bank
12 exercisesIf the weather is good, we ___ go for a hike.
You would can join the club if you register online.
Choose the correct sentence:
Translate into English: 'Si termino mi trabajo, puedo ayudarte.'
Arrange these words into a sentence:
Match the 'if' clause with its appropriate 'can' result:
If I save enough, I ___ travel next summer.
If they had finished on time, they can relax now.
Which sentence is correct?
Translate into English: 'Puedes usar mi coche si lo devuelves mañana.'
Arrange these words into a sentence:
Match the beginning of the sentence to its ending:
Score: /12
よくある質問 (8)
Yes, but it changes the meaning. `Can` is for real/likely situations (First Conditional). `Could` is for imaginary/unlikely situations (Second Conditional).
Usually 'If I'. For example: 'If I go, I can buy it.' If you say 'If I can go', you are saying 'If I have the ability to go'.
In English, you cannot put two modal verbs together. You must use `can` alone or the phrase `will be able to`.
Only if the `if` clause comes first. 'If it rains, we can stay.' (Comma) vs 'We can stay if it rains.' (No comma).
Yes, `may` is more formal than `can` but follows the same rule: 'If it rains, we may stay home.'
It's for the future and for general truths/rules. 'If you have a ticket, you can enter' is a general rule.
The negative is `cannot` or `can't`. Example: 'If you don't pay, you can't stay.'
Yes! 'Can we go if I finish my work?' is a very common way to ask for permission.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
Si + presente, poder (presente)
Spanish allows the future of 'poder', English does not allow 'will can'.
Si + présent, pouvoir (présent)
French speakers must avoid using the future after 'si', just like in English.
Wenn + Präsens, kann...
Word order: German moves the verb 'kann' to the start of the second clause.
〜たら、〜ことができる
Japanese marks the condition on the verb itself, not with a separate word like 'if'.
In + present, yumkin...
Arabic has several words for 'if' depending on how likely the situation is.
如果... 就可以...
Chinese grammar is very similar here, but it doesn't have verb conjugations for 'if'.
Learning Path
Prerequisites
Learn These First
関連動画
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