Условные предложения нулевого типа (Zero Conditional)

When you use it

The zero conditional describes what happens every time a condition is met: if you heat ice, it melts. It covers laws of nature, personal habits, house rules and instructions for machines. There is no particular occasion in mind and no doubt about the result; the sentence is true in general. Because of that, if and when mean almost the same thing here, and both are common.

How it is formed

If-clause (condition)	Main clause (result)
if / when + present simple	present simple
If you heat ice,	it melts.
When Tom is tired,	he goes to bed early.
If I don't drink coffee,	I get a headache.

Both halves use the present simple. Remember the third-person -s (melts, goes, gets) and the auxiliary do/does in negatives and questions: if it doesn't rain, does the grass die?

The order of the halves is free. With the if-clause first, use a comma; with the main clause first, no comma: ice melts if you heat it.

The main clause can also be an imperative. This is the normal form for instructions and warnings: if the phone rings, answer it; if the light is red, wait.

Use	Example
fact of nature	If water freezes, it expands.
habit	When Anna reads in the car, she gets sick.
rule or instruction	If you press this button, the door opens.
imperative result	If the alarm rings, leave the building.

The difference from the first conditional is in the main clause. Present simple there means "this always happens"; will means "this will happen on one future occasion". If you heat ice, it melts is a fact. If you leave the ice on the table, it will melt is a prediction about the ice in front of you.

Ukrainian and Russian express the same idea with the present tense in both halves: якщо нагріваєш лід, він тане; если нагреваешь лёд, он тает. The structure transfers well. The things that need attention are the English verb endings and the choice between present and will.

Examples

• If you heat ice, it melts.
• When I drink coffee at night, I don't sleep well.
• If Tom is tired, he goes to bed early.
• Plants die if they don't get enough water.
• If the phone rings, please answer it.
• Anna gets a headache if she reads in the car.
• When it snows, the buses are always late.
• If you press this button, the door opens.

Common mistakes

• ✗ If you heat ice, it will melt. (as a law of nature)
  ✓ If you heat ice, it melts.
  Will points to one future occasion. A general truth takes the present simple in both halves. Will is not wrong if you mean a specific piece of ice in front of you.
• ✗ If he is tired, he go to bed early.
  ✓ If he is tired, he goes to bed early.
  Both halves are present simple, so the third-person -s applies to the main verb too. Slavic verbs mark the person as well (він іде / он идёт), but the English ending is easy to forget after a long if-clause.
• ✗ If you will press this button, the door opens.
  ✓ If you press this button, the door opens.
  Якщо натиснеш / если нажмёшь is a future form, but the English if-clause stays in the present in every conditional at this level.
• ✗ When I am drinking coffee at night, I don't sleep well.
  ✓ When I drink coffee at night, I don't sleep well.
  Imperfective п'ю / пью describes repeated action and looks like it should become the continuous. English uses the present simple for habits and general truths; the continuous is for what is happening right now.
• ✗ If I wake up, I make coffee. (meaning: every morning)
  ✓ When I wake up, I make coffee.
  If suggests the condition may not happen. For something that happens on every occasion, when is the natural word, exactly as коли / когда would be in the mother tongue.

Try it