Zero and First Conditional

Zero and First Conditional

Conditional sentences talk about "if" situations and their results. The Zero Conditional talks about general truths and facts. The First Conditional talks about real, possible situations in the future.

Structure

• Zero Conditional: If + present simple, + present simple. Example: If you heat ice, it melts.
• First Conditional: If + present simple, + will + base verb. Example: If it rains, I will stay home.

How the Grammar Works

1. Use the Zero Conditional for things that are always true — scientific facts, habits, general rules: 'If you mix red and blue, you get purple.'
2. Use the First Conditional for a specific, realistic future situation: 'If I finish early, I will call you.'
3. The 'if' clause always uses the present simple, even though the meaning can be about the future — never use 'will' after 'if'.
4. The two parts can switch order. If 'if' comes second, no comma is needed: 'I will stay home if it rains.'

Common Use Cases

• Explaining facts and natural results: If you don't water plants, they die.
• Talking about habits and routines: If I'm tired, I go to bed early.
• Making real future plans and predictions: If we hurry, we'll catch the train.
• Warning about consequences: If you touch that, you'll get hurt.

Frequent Mistakes and How to Avoid Them

• Using 'will' in the if-clause: Incorrect: "If it will rain, I will stay home." Correct: "If it rains, I will stay home."
• Using 'will' for general truths: Incorrect: "If you heat ice, it will melt" (as a fact). Correct: "If you heat ice, it melts."
• Forgetting the comma when 'if' starts the sentence: "If it rains I will stay home" should be "If it rains, I will stay home."

Comparison with Related Grammar

The Zero Conditional describes something that is always true (both parts in present simple). The First Conditional describes something that is possible in the future (if + present simple, will + verb). If the result is guaranteed and general — use zero. If it's a specific future possibility — use first.

Example Sentences

• If you freeze water, it turns into ice. (zero)
• If I see him, I will tell him. (first)
• Plants die if they don't get sunlight. (zero)
• If you study hard, you will pass the exam. (first)
• If she calls, I will let you know. (first)

When to Use This Rule

Use the Zero Conditional for facts that are always true. Use the First Conditional for real, possible future situations. Both use the present simple after 'if' — never 'will'.