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C1 — 「If」のその先へ。洗練された条件表現を使いこなそう

C1 · 上級チャプター 19

「If」のその先へ。洗練された条件表現を使いこなそう

5 トータルルール

58 例文

7 分

このチャプターのルールクイック練習

Chapter in 30 Seconds

Master nuanced conditionality to express complex requirements, exceptions, and precautions with native-level precision.

Differentiate between negative conditions and standard hypothetical scenarios.
Integrate formal conditional conjunctions into professional and academic writing.
Apply precautionary phrasing to convey foresight in real-world contexts.

Refine your logic, elevate your precision.

学べること

いつまでも「If」ばかり使っていませんか？C1レベルを目指すなら、状況に応じて言葉を使い分ける「表現の解像度」を上げることが不可欠です。この章では、単なる条件提示を超えた、ネイティブが日常やビジネスで多用する5つの高度な表現をマスターします。例えば、例外をスマートに伝える 'Unless' や、契約や強い約束事で重宝する 'Provided that'、さらに「万が一に備えて」と準備を促す 'In case' など、状況を的確に伝えるスキルを磨きましょう。「もし〜なら」を卒業し、ビジネスでの細かな条件交渉や、友人との深い仮定の話（Supposing）を自信を持ってリードできるようになるのがこの章のゴールです。これらのルールを繋ぎ合わせることで、あなたの英語はぐっと自然で、無駄のない洗練された印象に変わります。ただ意味が通じるだけでなく、相手に信頼感を与える「大人の英語力」を一緒に手に入れましょう！

「Unless」をマスターする：例外の達人
「Unless」を使えば、例外をスマートに伝えられます。あなたのC1英語が「sharp」、「confident」、そして「naturally fluent」になる魔法のツールですよ！
条件: '〜する限り' (期間と条件)
「as long as」は、上級者として「微妙な条件」や「期間」をプロのように表現するための魔法のチケットだよ！
条件付き取引: 'Provided that' および 'Providing that'
「if」だけではない、よりフォーマルで強力な条件を表現するために、「provided that」と「providing that」という2つの「魔法の言葉」を使って、条件節を「次のレベル」に引き上げましょう！
条件文「In Case」：予防策を表現する
「in case」は、これから起こるかもしれないことに備えて、今すぐ行動を起こすことを表すときに使います。「Proactive action」、「Future possibility」、「Preparation」というキーワードを覚えておくといいですよ！
もしものシナリオ：「Supposing」の使い方
「Supposing」は、あなたの仮定法をワンランクアップさせる魔法の言葉です。「intriguing」で、時には「challenging」な仮説の状況を、真剣に「consider」する時に使ってみましょう。

Learning Objectives

By the end of this chapter, you will be able to:

1
By the end you will be able to: Use 'unless' to express negative conditions without creating double negatives.
2
By the end you will be able to: Construct formal contractual or logical arguments using 'provided that'.

チャプターガイド

Overview

Are you ready to move beyond basic conditional statements and unlock a truly advanced level of English communication? As a C1 learner, you're already fluent, but true mastery lies in expressing complex ideas with nuance and precision. This chapter, "English beyond 'if': advanced conditions," is designed to empower you to do just that.

We'll dive deep into structures that allow you to articulate exceptions, set clear terms, express foresight, and explore hypotheticals with sophistication. Mastering these advanced conditionals isn't just about grammar; it's about gaining the ability to convey your thoughts and intentions with the exact shade of meaning you desire, making your C1 English grammar truly shine.

You'll discover how to wield 'Unless' to pinpoint exceptions, employ 'As long as' to define ongoing conditions, and utilize 'Provided that' to establish non-negotiable requirements. We'll also explore 'In Case' for proactive preparedness and 'Supposing' for engaging in rich, speculative discussions. These are the tools that native speakers use to navigate the complexities of daily conversation, business negotiations, and academic discourse.

By integrating these advanced conditionals into your repertoire, you'll communicate with greater confidence, clarity, and the natural fluidity expected of a highly proficient English speaker.

How This Grammar Works

These advanced conditionals each add a specific flavor to your expression of conditions, moving beyond the simple

if A, then B

structure. They allow for greater precision and naturalness in your language.

First up, Unless: Think of this as the master of exceptions. It means if not, but it specifically highlights the *single exception* that would prevent a primary action or result. For example: "The team won't succeed unless everyone collaborates effectively." Here, effective collaboration is the one thing that prevents failure.

Next, As long as: This conditional links a result to a continuous condition that often functions as a time-based agreement or understanding. It implies duration.

You can borrow my car as long as you return it by midnight.

The condition (returning by midnight) is ongoing until the deadline, allowing the action (borrowing the car).

Then we have Provided that and Providing that: These are strong, formal ways to set clear, restrictive conditions. They mean only if or

on the condition that.

The result depends entirely on this one specific requirement being met.

The company will invest in your startup provided that you secure additional funding.

The investment is absolutely contingent on that funding.

In Case: This structure is all about expressing precautions. You do something now to be prepared for a possible future event, not because that event *is* happening, but *in anticipation* of it. "I'll bring my laptop charger, in case my battery dies during the meeting." You're preparing for a possibility, not responding to a certainty.

Finally, Supposing: This is your go-to for what-if scenarios, inviting others into a hypothetical situation. It adds a sophisticated, speculative layer to your English. "Supposing we miss our flight, what's our backup plan?" It opens up a discussion about possibilities without stating a firm condition.

Each of these structures serves to refine your conditional statements, allowing you to articulate nuanced relationships between actions and outcomes.

Common Mistakes

1Confusing 'in case' with 'if':

✗ I'll take an umbrella if it rains. (This means you'll only take the umbrella *after* it starts raining.)

✓ I'll take an umbrella in case it rains. (This means you're taking it *now* as a precaution against possible future rain.)

*Explanation*: 'If' states a direct condition; 'in case' states a precaution taken *before* a potential event.

1Using 'unless' for general negative conditions:

✗ You'll get sick unless you eat healthy. (While grammatically possible, 'unless' implies a sole exception. This phrasing is less natural for a general positive outcome.)

✓ You won't get sick unless you eat healthy. (This is correct. Eating healthy is the *exception* to getting sick; if you don't, you *will* get sick.)

*Explanation*: 'Unless' is best used when the condition is the *only* thing that will prevent a negative outcome or enable a positive one. Often, it pairs naturally with negative main clauses.

1Underestimating the formality/strength of 'provided that':

✗ You can come to the party provided that you bring a snack. (While possible, 'provided that' feels too strong for such an informal request.)

✓ You can come to the party if you bring a snack. (More natural for a casual condition.)

✓ Your contract will be renewed provided that you meet all performance targets. (Appropriate for a strong, formal condition.)

*Explanation*: 'Provided that' implies a much stricter, often non-negotiable condition than a simple 'if'. Choose your words to match the context's formality and the condition's weight.

Real Conversations

Scenario 1: Planning a Trip

Have you packed everything for the hike?

Almost! I'm just double-checking my first aid kit, in case we get any blisters.

Good idea! We won't reach the summit on time unless we start before sunrise.

Agreed. And we can camp near the lake as long as we find a suitable spot by evening.

Scenario 2: A Business Agreement

So, the merger will proceed?

Yes, provided that all legal documents are signed by Friday. There's no room for delays.

Understood. And we'll provide the necessary funds as long as the integration plan stays on schedule.

Excellent.

Scenario 3: A Hypothetical Discussion

This new AI technology is incredible.

It is! Supposing it could genuinely replicate human consciousness, what would that mean for society?

Well, unless we establish strong ethical guidelines now, it could lead to some really complex dilemmas.

True. It's a fascinating thought experiment.

Quick FAQ

What's the main difference between in case and if?

If describes a direct condition where one action happens *because* another happens (e.g., "If it rains, I'll stay home

). In case describes a precaution you take *before* a possible event, to be prepared for it (e.g.,

I'll take an umbrella in case it rains").

Can I use providing that and provided that interchangeably?

Yes, generally you can. Both provided that and providing that function identically to introduce a strong, restrictive condition, though provided that is slightly more common and often preferred in formal contexts.

Is supposing formal or informal?

Supposing is versatile. It can be used in both informal, conversational settings (

Supposing we go out tonight?

) and more formal, speculative discussions or academic contexts (

Supposing these variables change, what would be the outcome?

). Its usage lends an air of thoughtful speculation.

How does unless differ from except if?

While they are often similar in meaning, unless tends to be more concise and focuses on the *single exception* that prevents something from happening. Except if can feel a bit more clunky and is sometimes used to introduce a broader range of exceptions. "You won't get the discount unless you're a student

is more natural than

You won't get the discount except if you're a student."

Cultural Context

Native English speakers use these patterns to express precision and nuance. Provided that is quite formal and is frequently heard in legal, contractual, or academic settings, less so in everyday chat. In case is extremely common in daily conversation, reflecting a practical, planning-oriented mindset.

As long as also enjoys wide usage for setting clear boundaries or conditions in both formal and informal contexts. Unless is a staple for defining exceptions, while supposing is excellent for fostering hypothetical discussions, whether serious or lighthearted, adding a sophisticated touch to your speculative language.

重要な例文 (8)

I won't eat pizza unless it has pineapple.

パイナップルが乗ってないピザは食べません。

「Unless」をマスターする：例外の達人

You can't play outside unless your homework is done.

宿題が終わらない限り、外で遊んではいけません。

「Unless」をマスターする：例外の達人

You can borrow my car as long as you fill the tank.

ガソリンを満タンにしてくれるなら、私の車を借りていいよ。

条件: '〜する限り' (期間と条件)

As long as it's sunny, we'll have our picnic outside.

晴れていれば、外でピクニックをする予定です。

条件: '〜する限り' (期間と条件)

You can borrow my car, `provided that` you fill up the tank.

私の車を借りてもいいですが、ガソリンを満タンにすることが条件です。

条件付き取引: 'Provided that' および 'Providing that'

We will start the meeting on time, `providing that` everyone is present.

全員が出席していれば、会議は時間通りに開始します。

条件付き取引: 'Provided that' および 'Providing that'

I'll charge my phone fully `in case` the power goes out during the storm.

嵐で停電するかもしれないから、スマホをフル充電しておこう。

条件文「In Case」：予防策を表現する

Please send me the document again `in case` I didn't receive the first one.

最初のを受け取っていないといけないので、もう一度書類を送ってください。

条件文「In Case」：予防策を表現する

ヒントとコツ (4)

💡

UnlessとIf Notの違い

どちらも似ていますが、「unless」はより自然で簡潔に聞こえることが多いんです。「except if」といった明確な例外を強調したい時に使うと、文章がより洗練されてスマートになりますよ。「We won't go unless it's sunny.」

frontend.learn_grammar.from_rule: 「Unless」をマスターする：例外の達人

💡

「Only If」や「Provided」に置き換えて考えてみよう

「as long as」を使うべきか迷ったら、心の中で「only if」や「provided that」に置き換えてみて。もし文が自然で、伝えたいニュアンスが合っているなら、正解だよ。「If you're unsure if 'as long as' fits, try replacing it mentally with 'only if' or 'provided that'.」

frontend.learn_grammar.from_rule: 条件: '〜する限り' (期間と条件)

💡

「That」は省略可能

「provided that」や「providing that」が標準ですが、よりインフォーマルな会話や文章では「that」を省略しても大丈夫です。例えば、「provided you agree」のように使えます。フォーマルな文書では、明確にするために「that」を残しておきましょう。

frontend.learn_grammar.from_rule: 条件付き取引: 'Provided that' および 'Providing that'

💡

「先を見越した準備」と考える

「in case」は、将来起こるかもしれない出来事に備えて、*今*何かをするという意味だと常に覚えておいてくださいね。単なる反応ではなく、「予見」がポイントです。「if」が条件が満たされた*後*の反応を意味するのとは対照的ですよ。「I'll bring my laptop charger in case the battery runs out.」

frontend.learn_grammar.from_rule: 条件文「In Case」：予防策を表現する

重要な語彙 (5)

Precaution preventive measure Stipulation a condition or requirement Hypothetical based on a suggested idea Exception a person or thing excluded Conjunction a word used to connect clauses

Real-World Preview

briefcase

The Contract Negotiation

Review Summary

Unless + positive verb = If + negative verb
As long as + condition, result
Provided that + condition, result
Result + in case + precaution
Supposing + hypothetical condition, result

よくある間違い

Unless already contains the negative 'not'. Adding 'don't' creates a double negative.

Wrong: Unless you don't study, you will fail.

正解: Unless you study, you will fail.

In English, we typically use the present tense after 'in case' for future precautions.

Wrong: Take an umbrella in case it will rain.

正解: Take an umbrella in case it rains.

Provided that sets a condition for success, not a consequence of failure.

Wrong: Providing that you are late, we will start.

正解: Provided that you are on time, we will start.

このチャプターのルール (5)

Next Steps

You've navigated the complexities of conditions with ease. Keep practicing these in your daily writing, and you'll soon be using them intuitively!

Write a formal email using at least three of these conditional patterns.

Continue to: Imaginary Situations and Mixed Times

クイック練習 (10)

文中の間違いを見つけて修正しましょう。

Find and fix the mistake:

She won't apologize unless she isn't wrong.

✓ Correct! ✗ Not quite. Correct answer: She won't apologize unless she is wrong.

「Unless」は既に否定的な意味（〜でなければ）を含んでいるので、「isn't」は二重否定になります。正しい形では、「unless」の後に肯定動詞を使います。

frontend.learn_grammar.from_rule: 「Unless」をマスターする：例外の達人

文を完成させる正しい動詞の形を選びましょう。

Take an extra battery pack ___ your phone dies.

✓ Correct! ✗ Not quite. Correct answer: in case

ここでは「in case」を使って、起こりうる未来の出来事（電話のバッテリー切れ）に対する予防策（予備のバッテリーパックを持っていくこと）の理由を表現しています。

frontend.learn_grammar.from_rule: 条件文「In Case」：予防策を表現する

文中の間違いを見つけて修正しましょう。

Find and fix the mistake:

You should call him if you won't be able to make it to the meeting.

✓ Correct! ✗ Not quite. Correct answer: You should call him in case you are not able to make it to the meeting.

先を見越した通知には「in case」がより適切で、未来の可能性に対して「in case」の後に続くのは現在単純形の「are not able」です。

frontend.learn_grammar.from_rule: 条件文「In Case」：予防策を表現する

「in case」を正しく使っている文を選びましょう。

Choose the correct sentence:

✓ Correct! ✗ Not quite. Correct answer: I'll bring snacks in case I get hungry later.

未来の可能性に対する「in case」の正しい使い方では、「in case」節に現在単純形が必要で、「will get」は使いません。

frontend.learn_grammar.from_rule: 条件文「In Case」：予防策を表現する

正しく「unless」を使っている文を選びましょう。

Choose the correct sentence:

✓ Correct! ✗ Not quite. Correct answer: You won't understand unless you read the instructions.

最初の選択肢は二重否定を使っていて間違っています。三番目の選択肢は意味が変わってしまいます。正しい文は「unless」を「あなたが指示を読まなければ」という意味で使っています。

frontend.learn_grammar.from_rule: 「Unless」をマスターする：例外の達人

正しい文を選びましょう

正しい文を選びましょう：

✓ Correct! ✗ Not quite. Correct answer: The concert will happen providing that it doesn't rain.

未来の条件を表す「providing that」の後は、現在単純形（「doesn't rain」）を使い、未来形は使いません。

frontend.learn_grammar.from_rule: 条件付き取引: 'Provided that' および 'Providing that'

文を完成させる正しい選択肢を選びましょう。

I can't access the website ___ I know the password.

✓ Correct! ✗ Not quite. Correct answer: unless

「Unless」は「私がパスワードを知らないなら」という意味を正しく含んでいます。「If」を使うと、後ろの節で否定が必要になります。「until」は時間を指します。

frontend.learn_grammar.from_rule: 「Unless」をマスターする：例外の達人

文中の間違いを見つけて修正しましょう。

Find and fix the mistake:

You will get a promotion as long as you will work hard.

✓ Correct! ✗ Not quite. Correct answer: You will get a promotion as long as you work hard.

未来の条件に対して「as long as」を使う場合、「as long as」節の動詞は未来形ではなく現在形を使うべきです。

frontend.learn_grammar.from_rule: 条件: '〜する限り' (期間と条件)

文を完成させる正しい形を選びましょう。

Supposing she ___ (know) about the surprise, she wouldn't have looked so shocked.

✓ Correct! ✗ Not quite. Correct answer: had known

これはタイプ3の仮定法です。主節の「wouldn't have looked」は非現実の過去の状況を示しているので、「supposing」節には過去完了形（'had known'）が必要です。

frontend.learn_grammar.from_rule: もしものシナリオ：「Supposing」の使い方

正しい形を選びましょう

You can download the file ___ you create an account.

✓ Correct! ✗ Not quite. Correct answer: provided that

「Provided that」が最もよく当てはまります。アクセスするための特定の必須条件を示唆しています。「If」は一般的すぎ、「unless」は意味を逆にしてしまいます。

frontend.learn_grammar.from_rule: 条件付き取引: 'Provided that' および 'Providing that'

Score: /10

よくある質問 (6)

「Unless」は基本的に「if not」（〜でなければ）や「except if」（〜の場合を除いて）という意味です。ある条件が満たされない場合に特定の結果を招くことを示します。例えば、「I won't leave unless you come」は「あなたが来ないなら私は出発しない」という意味になりますね。

「unless」と「if not」は多くの場合、置き換え可能ですが、「unless」の方が単一の例外を表現する際により簡潔で洗練された言い方になります。例えば、「We'll go unless it rains」は、その自然な響きから「We'll go if it does not rain」よりも好まれることが多いです。

「as long as」の主な機能は、何かが真実である、または起こるために満たされなければならない条件を導入することです。多くの場合、期間を暗示し、ある条件が「満たされている間ずっと」何かが真実である、という意味になります。

完全に互換性があるわけではありません。どちらも条件を導入しますが、「as long as」は「only if」（～の場合に限り）や「provided that」（～という条件で）というより強い意味合いを持ち、しばしば期間の含意があります。「if」はより一般的です。

これらは、主要な行動が起こるために満たされなければならない強い条件を導入します。「only if」や「on the condition that」という意味だと考えてください。何かを規定する感覚が加わります。例えば、「You can come, provided that you bring snacks.」

コアとなる意味では、それほど違いはありません！「Provided that」は、ややフォーマルで固定的な印象を与え、書面による合意でよく見られます。「Providing that」は、より能動的または継続的な感じがしますが、基本的には互換性があります。例えば、「Providing that you agree, we can proceed.」