What you'll learn
By the end of this lesson, you'll be able to talk about general facts, scientific truths, and habits using the zero conditional.
When do I use it?
Use the zero conditional when the result is always or generally true. It works for facts of nature, rules, and habits.
- If you heat water to 100 degrees, it boils.
- If I drink coffee at night, I can't sleep.
- If the traffic light is red, you stop.
The condition and the result are both true in the present. You can also swap the two parts: Water boils if you heat it to 100 degrees.
How do I form it?
if + present simple, present simple
- Conditional clause: If + subject + present simple, main clause: subject + present simple. If it rains, the ground gets wet.
- When the if-clause comes first, put a comma after it. When it comes second, no comma is needed.
Common mistakes for Spanish speakers
The biggest transfer error is putting "will" or "would" in the if-clause: "If you will heat the water" is wrong, it is "If you heat the water". Spanish "si calientas el agua, hierve" already uses the present in both halves, so keep both halves in the present simple. Do not use "would" here; that belongs to other conditionals. Also check word order: "who" or "when" clauses do not make this a conditional, so keep the pattern clean.
Zero conditional = always true. Both verbs stay in the present simple — no will, no would.
Practice
Multiple Choice
A2Which sentence is a correct zero conditional?
Fill in the Blank
A2If I this button, the machine starts.
Hint: With he/she/it the verb adds -s; here the subject is 'I', so it stays base form.
Find the Error
A2Practice Speaking
Apply what you've learned in a real conversation with AI feedback.
Level: A2