1. Overview:
The zero conditional is used to talk about facts and things that are always true. We use it when one thing happens, and then another thing always happens.
Structure:
If + present simple + present simple
2. Cases of Usage:
Case 1: To express scientific facts.
Example: If you heat water to 100 degrees Celsius, it boils.
Case 2: To describe general truths or habits.
Example: If it rains, the ground gets wet.
Case 3: To give instructions or rules.
Example: If you mix red and blue, you get purple.
3. Exceptions or Things to Pay Attention To:
The zero conditional only uses the present simple tense in both parts (if-clause and main clause).
Example: If you touch fire, it burns (not "burned" or "will burn").
