Conditionals are sentences with 'if'. They describe what happens, or what will happen, under certain conditions. Two of the most common and useful forms are the zero conditional (for facts and habits) and the first conditional (for real, possible future situations). Both are essential for everyday English.
Before you start — think honestly about your own teaching and experience.
Look at the examples. Answer each question before reading the explanation — this is how your students will learn too.
Read these sentences. What do they have in common? What is the structure of each one?
All of these sentences describe things that are always true — scientific facts, natural laws, and reliable cause-and-effect relationships. The structure is: If + present simple, present simple. Both verbs are in the present simple. We call this the zero conditional because it describes a zero possibility of being wrong — it is always true. The same structure is used for habits and general truths: 'If I drink coffee late, I can't sleep.' The 'if' here means 'whenever' — every time this condition is true, the result follows automatically.
Now look at these sentences. How are they different from the sentences above?
The structure is: If + present simple, will + infinitive. Notice: the if-clause still uses present simple — NOT will. The result clause uses will. This is the first conditional. The meaning is different from the zero conditional: these situations are not always true — they are real possibilities in the future. It might rain tomorrow. She might study hard. We might leave now. The speaker thinks these situations are possible and likely. The zero conditional = always true. The first conditional = possible in the future.
Look at these two sentences. They look similar but mean different things.
The zero conditional version states a universal fact — fire always burns when touched. It is always true, for everyone, in every situation. The first conditional version refers to a specific real situation — there is a real fire nearby and the speaker is warning the listener about what will happen if they touch it. The key distinction: zero = universal truth, first = specific real possibility. In practice, the difference is often small and context makes it clear. But when teaching students, the clearest test is: Is this always true? → zero conditional. Is this a real possibility in this specific situation? → first conditional.
| Tense / Form | Use / Meaning | Example | Key time words |
|---|---|---|---|
| Zero Conditional | Facts, habits, universal truths — always true | If you heat ice, it melts. | when, every time |
| Zero Conditional | Cause and effect — reliable and automatic | If students are tired, they find it hard to concentrate. | whenever, if |
| First Conditional | Real possibility in the future — likely or possible | If it rains tomorrow, we will cancel the trip. | tomorrow, soon, tonight |
| First Conditional | Warning or promise about a real future situation | If you practise every day, your English will improve. | if, when (for certainty) |
THE MOST IMPORTANT RULE — never use 'will' in the if-clause:
This is the single most common error students make with conditionals at every level.
The if-clause always uses present simple for first conditional — even though it refers to the future. English uses present simple in if-clauses to describe future conditions. This feels strange to speakers of many other languages, where the future tense is used in both clauses.
IF vs. WHEN:
If = the speaker is not sure whether the condition will happen.
Ask: Is this always true, like a scientific fact? → zero conditional (present simple + present simple). Is this a real possibility in the future? → first conditional (present simple + will). Is 'will' in the if-clause? → always wrong. Change it to present simple.
Choose the correct form to complete each conditional sentence. Think about whether the situation is a fact (zero) or a real future possibility (first).
Each sentence contains an error. Write the correct version and explain why it is wrong — then reveal the answer.
Use this sequence directly in class — guided discovery, no textbook needed. Tap each step to mark it done.
STEP 1 — FACTS AND POSSIBILITIES (5 minutes): Say two sentences aloud and ask students which describes a fact and which describes a future possibility.
STEP 2 — NOTICE THE STRUCTURE (8 minutes): Write four zero conditional sentences on the board. Ask students to underline the verb in the if-clause and circle the verb in the result clause. What do they notice?
STEP 3 — THE CRITICAL RULE (5 minutes): Write this on the board:
STEP 4 — PERSONALISED PRACTICE (5 minutes): Ask students to complete these sentence starters — using their own real lives.
STEP 5 — ERROR HUNT (5 minutes): Write five conditional sentences on the board — some correct, some wrong. Students work in pairs to find and correct errors. Share and discuss. This consolidates the 'no will in if-clause' rule and the zero vs. first distinction.
Use directly in class — copy, adapt, or read aloud. No printing needed.
For each strategy, choose the option that best describes where you are now.
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