We use the so-called zero conditional when the result of the condition is always true, like a scientific fact.

Take some ice. Put it in a saucepan. Heat the saucepan. What happens? The ice melts (it becomes water). You would be surprised if it did not.

Eg.

If + Condition + Result

If + Pres. Simple + Pres. Simple (= Zero Conditional form)

If you heat ice, it melts

Notice that we are thinking about a result that is always true for this condition. The result of the condition is an absolute certainty. We are not thinking about the future or the past, or even the present. We are thinking about a simple fact. We use the present simple tense to talk about the condition. We also use the present simple tense to talk about the result. The important thing about the zero conditional is that the condition always has the same result.

Note: We can also use when instead of if, for example: When I get up late I miss my bus.

More Examples:

If + Condition + Result

If I miss the 8 o’clock bus, I am late for work.

If I am late for work, my boss gets angry.

If people don’t eat, they get hungry.

If you heat ice, does it melt?

Result + if + Condition:

I am late for work if I miss the bus.

My boss gets angry if I’m late for work.

People get hungry if they don’t eat.

Does ice melt if you heat it?

Free Daily Lesson courtesy of http://www.internetenglishlearnonline.com

Learn and Speak English Online with IELO – Internet English Learn Online – Speaking Lessons, General English Classes, Exam Preparation Courses, English for Special Purposes, Jobseekers English, Document Editing and Custom English Courses designed just for you!