Zero conditional
Zero conditional is used to describe scientific facts and direct correlations, dive into the world of certainty!
Before this, learn: Present SimpleClauses
1.Clauses Recap
1.1The Basics
A clause is a group of words that contains a subject and a verb. It can function as a whole sentence (a main clause) or as part of a sentence (a subordinate clause).
| Main Clause | Subordinate Clause (needs more information to be a full sentence) |
|---|---|
| also called Independent Clause expresses a complete thought and can stand alone as a sentence |
also called Dependent Clause does not express a complete thought and cannot stand alone; needs to be connected to an independent clause. |
| Examples: | Examples: |
| She will help me. I would go for a walk. We'll go out. You'll pass the test. |
If I ask her about it If it weren't that cold If the meeting ends If you study hard |
| There are different types of Subordinate clauses (see Topic Clauses). |
| We normally express a condition using an if - clause with a main clause. |
| Conditional sentences / Conditionals are often categorised as: Zero, First, Second, Third, Mixed and False. |
2.Zero Conditional REAL / Structure
2.1Standard Forms
The zero conditional expresses general truths, scientific facts, natural laws, and things that always happen under certain conditions. It describes cause-and-effect relationships that are always true.
Remember that in zero conditional sentences, you can often replace if with when or whenever without changing the meaning!
| Rules and Tenses Standard Form |
Examples | Context |
|---|---|---|
| If: Present Simple Main: Present Simple |
If you heat water to 100°C, it boils. | Scientific fact about the boiling point of water. |
| If I eat too much sugar, I get sick. | Personal physical reaction that always occurs. | |
| If: Past Simple Main: Past Simple |
If it rained, the streets flooded. | Regular past occurrence - whenever it rained in that area, flooding always happened |
| If I ate dairy, I got sick. | Past physical reaction that always occurred | |
| If the alarm rang, everyone evacuated the building. | Standard past procedure that was always followed |
Clause order: either clause can come first, and the meaning does not change. When the if-clause comes first, a comma separates the two clauses; when the main clause comes first, there is no comma.
| Clause Order Standard Form |
Examples | Comma |
|---|---|---|
| If + Present Simple, Present Simple | If you heat water to 100°C, it boils. | Comma after the if-clause |
| Present Simple + if + Present Simple | Water boils if you heat it to 100°C. | No comma |
| If + Past Simple, Past Simple | If it rained, the streets flooded. | Comma after the if-clause |
| Past Simple + if + Past Simple | The streets flooded if it rained. | No comma |
Test yourself
2.2Alternative Forms
Remember that in zero conditional sentences (used for general truths, scientific facts, or always-true situations), you can often replace if with when or whenever without changing the meaning!
| Rules and Tenses Alternative |
Examples | Context |
|---|---|---|
| If: Present Progressive (Continuous) Main: Present Simple |
If you are working late, you miss dinner. | Habitual consequence when the ongoing action of working late occurs |
| If: Present Simple Main: Present Progressive (Continuous) |
If it rains, people are running for shelter. | Describes the typical ongoing reaction when rain occurs |
| If: Present Perfect Main: Present Simple |
If you have eaten breakfast, you feel energetic. | General truth about the relationship between eating breakfast and feeling energetic |
| If: Present Simple Main: Imperative |
If you feel tired, take a break. | General advice or instruction |
| If: Past Progressive (Continuous) Main: Past Simple |
If I was working late, I missed dinner. | Habitual past consequence of ongoing late work |
| If: Past Simple Main: Past Progressive (Continuous) |
If the phone rang, she was always running to answer it. | Typical ongoing past reaction to a trigger |
| If: Past Simple Main: used to/would + base verb |
If winter came, we would migrate south. | Past habitual behaviour triggered by seasonal change |
| If it snowed, schools used to close immediately. | Past institutional policy that was regularly implemented | |
| If: Past Progressive (Continuous) Main: Past Progressive (Continuous) |
If I was studying, my roommate was always making noise. | Simultaneous ongoing past actions that regularly occurred together |
3.Use
3.1General truths
The zero conditional expresses general truths - statements that are universally accepted as true.
We use zero conditionals for facts, habits, and inevitable results, not hypothetical situations.
If = When = Whenever (in zero conditionals, they often mean the same thing).
| Examples |
|---|
| If you mix blue and yellow, you get green. If you don't water plants, they die. If you heat butter, it melts. If you drop an apple, it falls to the ground. If you don't sleep enough, you feel tired. |
Test yourself
3.2Scientific Facts
The zero conditional expresses scientific facts - objective, proven facts in science.
We use zero conditionals for facts, habits, and inevitable results, not hypothetical situations.
If = When = Whenever (in zero conditionals, they often mean the same thing).
| Examples |
|---|
| If you boil water at sea level, it reaches 100°C. If you combine hydrogen and oxygen, you get water (H₂O). If you expose iron to oxygen and moisture, it rusts. If you cool water below 0°C, it freezes. If you mix vinegar and baking soda, they create a reaction. |
Test yourself
3.3Natural Laws
The zero conditional expresses natural laws - unchangeable laws of nature or physics.
We use zero conditionals for facts, habits, and inevitable results, not hypothetical situations.
If = When = Whenever (in zero conditionals, they often mean the same thing).
| Examples |
|---|
| If an object is in motion, it stays in motion unless acted upon. (Newton's First Law) If you drop something, gravity pulls it downward. If you light a fire, it produces heat and light. If you push an object, it moves (unless friction stops it). If you increase temperature, gas expands. |
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3.4Things That Always Happen Under Certain Conditions
The zero conditional expresses things that always happen under certain conditions - results that are 100% predictable.
We use zero conditionals for facts, habits, and inevitable results, not hypothetical situations.
If = When = Whenever (in zero conditionals, they often mean the same thing).
| Examples |
|---|
| If you press this button, the machine turns on. If you eat too much sugar, your blood sugar rises. If you don't charge your phone, the battery dies. If you leave milk outside, it spoils. If you flip the switch, the light turns on. |
Test yourself
3.5Cause-and-Effect Relationships / Always True
The zero conditional expresses Cause-and-Effect relationships (always true) - one action inevitably leads to another.
We use zero conditionals for facts, habits, and inevitable results, not hypothetical situations.
If = When = Whenever (in zero conditionals, they often mean the same thing).
| Examples |
|---|
| If you study hard, you learn more. If you exercise regularly, your body gets stronger. If you touch fire, you get burned. If you add salt to food, it becomes saltier. If you don't wear sunscreen, you get sunburned. |
Test yourself
4.Frequently asked questions
When do you use the zero conditional?
Use the zero conditional for things that are always true when a condition is met: general truths, scientific facts, habits and predictable results. Both clauses use the present simple: "If you heat ice, it melts" or "If I drink coffee late, I can't sleep". The if-clause can come first or second without changing the meaning: "Water boils if you heat it to 100°C". The zero conditional is not for imaginary situations; for those, English uses the second conditional.
Zero conditional vs first conditional: what's the difference?
The zero conditional describes what always happens, while the first conditional describes one possible future situation and its result. The zero conditional uses the present simple in both clauses; the first conditional uses will in the main clause. Compare "If it rains, the roads get wet" (this happens every time) with "If it rains tomorrow, the match will be cancelled" (one particular future event).
Can you use will in the zero conditional, as in "If you heat ice, it will melt"?
For a general truth, the present simple in both clauses is the usual choice: "If you heat ice, it melts". "It will melt" is also correct English, but it turns the fact into a prediction about one situation, which makes it a first conditional. Don't put will in the if-clause of a zero conditional: say "If you mix blue and yellow, you get green", not "If you will mix blue and yellow, you get green".
If or when in the zero conditional: is there a difference?
In the zero conditional, if and when usually mean the same thing, like "whenever", because the result follows every time. "If you press this button, the machine turns on" and "When you press this button, the machine turns on" say the same. When can sound a little more regular, and if can suggest it doesn't happen often: "When I travel, I take a book" and "If I travel, I take a book" are both correct.
Can you use an imperative in the zero conditional, as in "If you feel tired, take a break"?
Yes: the main clause of a zero conditional can be an imperative, to give an instruction or advice that applies every time. "If you feel tired, take a break" and "If the alarm rings, leave the building" are both correct. The if-clause stays in the present simple: say "If you see smoke, call the fire brigade", not "If you will see smoke, call the fire brigade". The imperative is the base form of the verb with no subject: "take", "leave", "call".
