Zero and first conditional
规则
Zero conditional states universal facts and regular habits, while first conditional predicts a specific future occasion.
The Zero and First Conditionals are grouped together in English linguistics as Real Conditionals because both deal with realistic, non-hypothetical situations. However, they serve very different communicative purposes: (1) Zero Conditional (Universal Laws, Scientific Facts, and Habits): Focuses on what happens generally and inevitably whenever a condition is met. The time frame is all time, and the result is an automatic certainty. Formula: If / When + Present Simple, Present Simple ("If water reaches zero degrees, it freezes", "If you press this button, the green light turns on"). Because the outcome is 100% predictable, when can freely replace if without changing meaning: "When it rains, the grass gets wet". (2) First Conditional (Specific Future Predictions and Plans): Focuses on a specific single occasion in the future. The condition is realistically possible, and the result is a probable outcome if that condition occurs. Formula: If + Present Simple, will / can / might + bare base verb ("If it rains tomorrow afternoon, we will cancel our outdoor soccer match"). Here, if and when are NOT interchangeable: using when implies the speaker is certain the event will happen ("When the train arrives, I will call you"), while if expresses genuine contingency.
记住
- Zero conditional uses present simple in both clauses: if you press the button, the bell rings.
- First conditional uses present simple after if and will in the result: if you help me, I will help you.
- When can replace if in the zero conditional when the condition happens regularly and reliably.
需要避开的常见陷阱
Never put will in the condition clause after if: say if the train arrives on time, never if the train will arrive.
Guía visual
How to read this B1 topic
At B1, grammar links ideas: condition, result, reported meaning, experience, and narrative order.
1. Name the relationship
Ask whether the sentence gives a condition, contrast, cause, report, or result.
If it rains, we will stay home.
2. Separate time from aspect
Finished event, visible result, duration, and background action use different forms.
I had left before she arrived.
3. Test both clauses
In complex sentences, the second half often proves the first half.
I wish I knew.
Conditional patterns
Read both halves. The result clause often tells you which condition pattern is needed.
| Meaning | If-clause | Result clause | Example |
|---|---|---|---|
| general truth | present simple | present simple | If water freezes, it expands. |
| real future | present simple | will + base verb | If it rains, we will stay. |
| imaginary present | past simple | would + base verb | If I knew, I would tell you. |
| imaginary past | past perfect | would have + participle | If I had known, I would have called. |
Contrasts that often decide the answer
Event or background
Simple forms move events forward; continuous forms show an action in progress.
I left while she was talking.
Fact or stance
Modals, hedges, and reporting structures show how certain or responsible the speaker sounds.
This may indicate a problem.
Clause or compressed phrase
Advanced writing often compresses full clauses into participle, noun, or prepositional phrases.
Having reviewed the data, we revised the plan.
例句
- 1If you mix blue and yellow paint together, you get green paint every time.
- 2If the airline tickets are affordable next week, we will book our summer flight.
- 3When the temperature falls below freezing, ice forms on the mountain roads.
- 4She will definitely call you this evening if she finishes her meeting early.
- 5If customers do not receive their parcels within three days, the store refunds them.
- 6We will have a barbecue in the back garden on Sunday if the sunshine lasts.
- 7When iron is exposed to moisture and oxygen, it slowly rusts and deteriorates.
- 8If you do not set an alarm clock tonight, you will probably oversleep tomorrow.
- 9Plants wither and die if they do not receive adequate water and sunlight.
- 10If the train is delayed by more than thirty minutes, passengers will receive compensation.
例外
Modal Variations in the First Conditional Result: Although will is the default marker of future consequence, English frequently substitutes other modal verbs to express different degrees of certainty: can (ability/permission: "If you finish early, you can leave"); might or may (possibility: "If it rains, we might stay home"); should (advice: "If you feel feverish, you should rest").
常见错误
(1) Inserting will into the if-clause: "If you will help me, I will be grateful." → "If you help me, I will be grateful." (The condition clause takes present simple). (2) Confusing if and when in the first conditional: "When it rains tomorrow, we will stay home." (assuming rain is uncertain) → "If it rains tomorrow, we will stay home." (If expresses uncertainty). (3) Past tense in zero conditional: "If you heated water, it boils." → "If you heat water, it boils."
自我检测
Write two scientific or workplace facts with zero conditional and two future plans with first conditional, then practise.
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