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Unit 12
Zero & First Conditional
if + present / will
What are Conditionals?
Conditional sentences describe cause and effect — what happens, will happen, or could happen if a condition is met. They all contain an if-clause (the condition) and a result clause (what happens).
Zero Conditional — Facts & General Truths
- Used for things that are always true — natural laws, habits, general facts.
- If it rains, the grass gets wet.
- If you mix red and blue, you get purple.
- If people don't eat, they die.
- Tip: If can often be replaced by when for general truths: When water freezes, it expands.
| Structure | Use | Example |
|---|---|---|
| If + Present Simple, + Present Simple | Facts, rules, scientific truths — always true | If you heat water, it boils. |
First Conditional — Real Future Situations
- Used when the condition can actually happen — a real possibility.
- If you study hard, you 'll pass the exam.
- If I see her, I 'll tell her the news.
- If they don't hurry, they 'll miss the bus.
- Clause order: The if-clause can come first or second. We'll stay home if it rains.
| Structure | Use | Example |
|---|---|---|
| If + Present Simple, + will + base verb | Real, possible future situations | If it rains tomorrow, we 'll stay home. |
Zero vs First Conditional — Side by Side
| Zero Conditional | First Conditional |
|---|---|
| Always true — general fact or habit | Possible future — real situation |
| If + Present Simple, + Present Simple | If + Present Simple, + will + base verb |
| If you heat ice, it melts. | If you heat the soup, it will taste better. |
| If people eat badly, they get ill. | If she eats this, she 'll love it. |
| Can replace "if" with "when" | Cannot always replace "if" with "when" |
The Golden Rule — No "Will" in the If-Clause
Never use "will" in the if-clause of either conditional. Always use Present Simple there.
| Wrong ❌ | Correct ✅ |
|---|---|
| If it will rain, we'll stay home. | If it rains, we'll stay home. |
| If I will see her, I'll tell her. | If I see her, I'll tell her. |
| If you will help me, I'll finish faster. | If you help me, I'll finish faster. |
Variations — Modals & Imperatives
- Modals instead of will (softer tone): If you study, you might pass. / If you're tired, you should rest.
- Imperative in result clause: If you see Mark, tell him to call me.
- When instead of if (for certain future events): When I see her, I'll tell her. (= I'm sure I will see her)
Unless, As Long As & Time Clauses
| Word | Meaning | Example |
|---|---|---|
| unless | = if ... not | Unless you hurry, you'll miss the bus. (= If you don't hurry...) |
| as long as / provided (that) | = only if | You can borrow my car as long as you drive carefully. |
| when | sure it will happen | When I get home, I'll call you. |
| if | not sure it will happen | If I get the job, I'll buy a car. |
| as soon as / before / until | time clauses → present tense | I'll text you as soon as I arrive. |
Annotated Examples
Subject
Verb
Auxiliary
Object
Adjective
Adverb
Preposition
Hover over any word to see its role.
Ifverbyou heatobjectice,subjectitverbmelts.
↳ Zero Conditional — universal truth, both Present Simple.
Ifverbit rainsadverbtomorrow,subjectweverb'll stayobjecthome.
↳ First Conditional — real possibility, will in result clause.
Ifverbyou seeobjectMark,verbtellhim to call me.
↳ First Conditional with imperative in result clause.
Common Mistakes
If it will rain, we'll stay home.
→
If it rains, we'll stay home.
No "will" in the if-clause — use Present Simple.
If I will see her, I'll tell her.
→
If I see her, I'll tell her.
Present Simple in the if-clause, not will.
If I study, I passing the test.
→
If I study, I'll pass the test.
Result clause needs will + base verb.
If people doesn't eat, they die.
→
If people don't eat, they die.
"People" is plural → "don't", not "doesn't".
If water will freeze, it expands.
→
If water freezes, it expands.
Zero Conditional: Present Simple in both clauses.
Unless you don't study, you'll fail.
→
Unless you study, you'll fail.
"Unless" already means "if not" — don't add another negative.
I'll call you when I will arrive.
→
I'll call you when I arrive.
Present Simple after when / as soon as.