Zero Conditional
A2 · ElementaryConditionalsIf you heat water to 100 degrees, it boils. Always true — present simple in both parts.
What you'll learn
- The zero conditional uses present simple in both the if-clause and the main clause
- It describes things that are always true: general truths, scientific facts, habits
- 'When' can replace 'if' without changing the meaning
- The subject is always kept in the if-clause, even for general instructions
Always true: present simple + present simple
The zero conditional describes something that is always true — a general truth, a scientific fact, or a habitual result. Both clauses use the present simple tense, and there's no 'will' anywhere in the sentence.
'If' and 'when' are interchangeable here
Because a zero conditional describes something that always happens, 'if' and 'when' mean essentially the same thing — both introduce a condition that reliably leads to the same result.
Keep the subject in the if-clause
Even in general instructions or scientific statements, English keeps a subject (often 'you' for a general 'anyone') in the if-clause — it doesn't drop down to a bare instruction form.
Real English
Watch out
A zero conditional never uses 'will' — it's not about the future, it's about something that's always true, so present simple goes in both clauses.
Present simple, not 'will,' goes in the if-clause of a zero conditional.
English keeps a subject in the if-clause, even for a general instruction — never drop it to a bare verb form.
Real life — Explaining a habit
"Why do you always carry a water bottle?"
"If I don't drink enough water, I get headaches."
"Makes sense. I'm the same with coffee — if I skip my morning cup, I can't focus."
"Ha, same. When I don't sleep enough, I feel it all day too."
Practice
Exercise 1 · Choose the correct sentence
Choose the correct zero conditional sentence.
Exercise 2 · Choose the correct sentence
Choose the correct sentence.
Exercise 3 · Choose the correct tense
Which tense is used in BOTH clauses of a zero conditional?
Exercise 4 · Choose the correct sentence
Choose the correct sentence about a general truth.
Exercise 5 · Choose the correct sentence
Choose the correct sentence about a personal habit.
Exercise 6 · Choose the word that can replace 'if'
Which word can replace 'if' in a zero conditional without changing the meaning?
Exercise 7 · Choose the correct sentence
Choose the correct sentence.
Exercise 8 · Choose the correct sentence
Choose the correct sentence with a subject kept in the if-clause.
Exercise 9 · Complete the sentence
Complete the zero conditional: 'If you don't water plants, they ___ (die).'
Exercise 10 · Complete the sentence
Complete the zero conditional: 'Metal ___ (expand) if you heat it.'
Exercise 11 · Sort into groups
0 / 4 sorted
Quick challenge
Five quick questions to check what stuck.
Question 1 / 5
Score: 0/0
Choose the correct zero conditional sentence.
You learned
- The zero conditional uses present simple in both clauses.
- It describes general truths, scientific facts, and habits.
- 'When' can replace 'if' without changing the meaning.
- The subject is always kept in the if-clause.
Related grammar lessons
First Conditional
Learn the first conditional — present simple in the if-clause, will in the main clause — for real, likely possibilities in the future.
Second Conditional
Learn the second conditional — past simple in the if-clause, would in the main clause — for unreal or unlikely situations in the present or future.
Third Conditional
Learn the third conditional — past perfect in the if-clause, would have + past participle in the main clause — for imagining a different past.
Other Conditional Expressions
Learn alternative ways to express a condition — provided that, providing, on condition that, and as long as — and which register each one fits.