Zero and first conditionals
Talk about general truths (zero conditional) and real future possibilities (first conditional).
In this lesson you will
- Form zero and first conditionals
- Choose between them
- Use when vs if
Learn
Zero conditional — always true: If / When + present, present: If you heat ice, it melts. If I drink coffee late, I can’t sleep.
First conditional — a real possibility in the future: If + present, will + verb: If it rains, we’ll stay in. If you don’t hurry, you’ll miss the bus.
Never use will in the if-clause: If it rains** (not will rain). Other modals can replace will: If you’re free, we could meet.
when = sure it will happen; if = maybe: When I get home, I’ll call you. vs If I get the job, I’ll celebrate.
Examples
- If you mix red and yellow, you get orange.
- If I see Omar, I’ll give him your message.
- You’ll feel better if you get some sleep.
- When the film finishes, we’ll go for dinner.
Vocabulary
condition
something that must happen first
possibility
something that might happen
hurry
move quickly
celebrate
do something enjoyable for a special event
otherwise
if not
Practice
If you ___ water to 100 °C, it boils.
Speaking
Complete these with your own ideas: If I have time this weekend…, If I don’t sleep well…, When I finish this course…, If it rains tomorrow…
Writing
Write a short guide (60–80 words): “What happens if you…?” about your town, school or workplace rules.
Lesson quiz
If you don’t water plants, they ___.
Review
Key points
- Zero: if + present, present (truths).
- First: if + present, will (real future).
- No will after if; when = certain.
What you learned
- ✓ I can use zero and first conditionals.
- ✓ I avoid will after if.
- ✓ I know if vs when.
Grammar reference: Conditionals: zero, first, second and third