Grammar: Conditionals.

"Conditionals" are structures of English in which if a certain situation,condition or circumstance is true,then a specific result happens. Here we'll see some types of "conditionals":

Zero Conditional - (Type Zero): A situation that is always true

         Ex.If you freeze water, it turns into ice.

First Conditional - (Type I): A possible or real situation 

         Ex.If it rains today, I'll stay at home.

Second Conditional - (Type II): A hypothetical situation

         Ex.If I won the lottery, I would travel around the world.

Third Conditional - (Type III): A hypothetical situation that happened in the past

        Ex.If I had won the lottery, I would have traveled around the world.

-Conditional: wish + past simple - A desire about a situation that is not real

Ex.I wish I were rich (but I am not)

-Conditional: wish + past perfect - A desire about the past

Ex.I wish I had learned English when I was younger (but I didn't)

-Conditional: wish + would - Expressing irritation or displeasure

Ex.I wish you would stop making that noise

-Words to express conditions: unless, provided, ...

Ex.You won't pass the exam unless you study harder.

1.TYPE ZERO

This conditional refers to a situation which is always true (universal truths).The 'if' in this conditional can usually be replaced by 'when' without changing the meaning.

If you freeze water, it turns into ice.

Si congelas el agua, se convierte en hielo.

If I work too much, I get tired. 

Si trabajo demasiado, me canso.

If I have time, I usually go to the movies.

Si tengo tiempo, generalmente voy al cine.

If she eats hamburgers, she gets an allergy.

Si ella come hamburguesas, le da alergia.

2.TYPE I

Formed with if + simple present + simple future. It is used when a situation is possible or real.Of course, we can't know what will happen in the future, but this describes possible things, which could easily come true.

If it rains today, I'll stay at home.

Si llueve hoy, me quedaré en casa.

If he is busy now, I will come back tomorrow.

Si está ocupado ahora, regresaré mañana.

If I have time, I'll visit my parents this afternoon.

Si tengo tiempo, visitaré a mis padres esta tarde.

If it is warm tomorrow, we'll go to the beach.

Si está caluroso mañana, iremos a la playa.

3.TYPE II

It refers to a hypothetical situation and it is formed by if + simple past + simple conditional.

If I won the lottery, I would travel around the world.

Si ganara la lotería, viajaría por todo el mundo.

If I were in Brazil, I would go to Rio de Janeiro.

Si yo estuviese en Brasil, iría a Río de Janeiro.

If I were you, I would buy that car.

Si yo fuese tú, compraría ese auto.

If he were in my place, he wouldn't do this.

Si él estuviese en mi lugar, no haría esto.

4.TYPE III

It refers to a hypothetical situation from the past and it is formed with the structure if + past perfect + conditional perfect.It's used to describe a situation that didn't happen, and to imagine the result of this situation.

If I had won the lottery, I would have traveled around the world.

Si yo hubiera ganado la lotería, habría viajado por todo el mundo.

If I had seen him, I would have told him about you.

Si lo hubiese visto, le habría contado acerca de ti.

If I had known the answer, I would have raised my hand.

Si hubiese sabido la respuesta, habría levantado mi mano.

If she had come on Saturday, I would have seen her.

Si ella hubiese venido el sábado, la habría visto.

*(Notice we can put 'if' at the beginning, or in the middle. It doesn't matter at all.)