English Zero Conditionals

There are several types of conditional statements in English. Zero conditionals are those that state a fact or a generally understood truth, such as “ice melts when heated” or “the Earth is round.” The form is:

  If + present simple, present simple.

Examples:
If water boils, it evaporates.
If you don’t drink water, you die of thirst.
Bears attack if they are provoked.
When the temperature drops below 32 degrees Fahrenheit, water freezes.

Zero conditionals start with an “if” or “when” clause, followed by the main or independent clause. Note that in one of the examples above, the “if”-clause is located in the second half of the sentence (the main clause comes first). 

The function of the zero conditional is to make statements about the real world, and it is true now and will be in the future. Also, each situation is real and not hypothetical. Here are a few more examples written in various, acceptable ways:

If plants get water and sunshine, they grow.
When plants get water and sunshine, they grow.
Plants grow when they get water and sunshine.

If you wash your hands, they get clean.
Your hands get clean when you wash them.
When you wash your hands, they get clean.

The italicized words above are the main clauses, and “if” and “when” are in bold, marking the beginning of the if- and when-clauses, respectively.

Sometimes, the zero conditional, when combined with the imperative, can be used to give instructions. For example:

If John shows up, have him call me.
If you see a crime, report it to the police.
Email me if the apartment is still available.