As in all conditional sentences, the order of the clauses is not fixed. You may have to rearrange the pronouns and adjust punctuation when you change the order of the clauses, but the meaning is identical. In zero conditional sentences, you can replace "if" with "when", because both express general truths. The meaning will be unchanged.
When we are thinking about facts which are generally true, we use:
If + Present Simple, Present Simple
If you put water in the freezer, it becomes ice.
If you stand in the rain, you get wet.
If you heat ice, it melts.
You can see in the examples about the the condition always has the same result.
Notice how we use a comma after the first present simple tense clause.
We can also reverse the order and use:
Present Simple + If + Present Simple
You get wet if you stand in the rain.
Ice melts if you heat it.
I can't sleep if I drink coffee at night.
Plants die if you don't water them.
Notice how the comma is not necessary with this word order.
The Zero Conditional Structure
Take a look at this condition:
If I get lost,
This is not a complete sentence. There is some information missing. What happens if you get lost? What do you do? We need another clause to explain what happens.
Take a look at this result:
I ask for directions.
This is a complete sentence, but there is also some information missing. When do you ask for directions? Under what conditions do you ask for directions?
If I get lost, I ask for directions.
This is the easiest conditional sentence remember, because you use the present simple tense in both clauses of the sentence:
If + present simple, present simple
Now that you understand how to form the zero conditional, let’s focus on when to use it.
1. Habits
In English, use the present simple tense to talk about habits and daily routines:
I walk the dog every day. I call my mother once a week. I babysit my grandchildren every week.
You can also use the zero conditional sentence structure to talk about your habits, or things that you always do in certain situations or conditions.
Finish these sentences with what you do in these situations:
If I get sick, I … If I miss the train, I … If I don’t sleep well, I … If I drink, I … If it’s hot, I … If it snows, I …
Remember: You are thinking about your habits, not a specific situation that is happening today or that will possibly happen tomorrow.
Now, take a look at these sentences. Do you do these things? When do you do these things?
I stay home from work. I drive to work. I am cranky in the morning. I never drive. I go to the beach. I shovel the driveway.
These things are connected. Let’s put them together in the zero conditional sentence structure.
If this event or condition happens, this is what I do.
If I get sick, I stay home from work. If I miss the train, I drive to work. If I don’t sleep well, I am cranky in the morning. If I drink, I never drive. If it’s hot, I go to the beach. If it snows, I shovel the driveway.
EXAMPLES
If you heat ice, it melts.
Ice melts if you heat it.
When you heat ice, it melts.
Ice melts when you heat it.
If it rains, the grass gets wet.
The grass gets wet if it rains.
When it rains, the grass gets wet.
The grass gets wet when it rains.
The zero conditional is also often used to give instructions, using the imperative in the main clause.
EXAMPLES
If Bill phones, tell him to meet me at the cinema.
Ask Pete if you're not sure what to do.
If you want to come, call me before 5:00.
Meet me here if we get separated.
Complete the zero conditional sentences with the verb in brackets. Use contractions where possible.
it turnsI gothey don't have he's comes you aren'tI don't knowwe don't do
If you press that button, the light(come) on.
It's easier to sleep if(you / not / be) stressed.
The teacher gets angry if(we / not / work) hard.
If(I / go) on a boat, I always feel sick.
His mother gets annoyed if(he / be) late.
If(I / not / know) a word, I look in my dictionary.
They play football if(they / not / have) any homework.
A todos los alumnos que presentaran saberes previos en todos los niveles se les comunica que dicho examen se llevara acabo en la primera semana se febrero debido que son varios exámenes en comparacion con otras asignaturas por lo cual se les invita a asistir a todas sus clases con la finalidad de realizar dichos examanes a tiempo