1. CONDITIONAL SENTENCES
Connectors:
If… (si…)
If you agree to play with me, we will win the competition
Provided/Providing (that)…, as long as… = if and only if… (siempre y cuando…siempre que…)
Provided you agree to play with me, you will win the competition.
Unless… = if not… (a no ser que…)
Unless you agree to play with me, you will not win the competition.

2. CONDITIONAL SENTENCES
1st Type: Connector Present Simple…Will/Can/Must/May…
If you stay out at night, you will feel very tired the next morning
Real conditional: something possible and logical to happen.
2nd Type: Connector Past Simple…Would/Could/Should/Might…
If you stayed out at night, you would feel very tired the next morning
Unreal Conditional: A hypothesis or something difficult to happen. It is improbable.
If I were you , I would not stay out at night.
Would you go out at night if you were older?
Unreal situations: an example that can not be a real fact so as to express an idea. We change reality. I can’t be you and I can’t be older.
3rd Type: Connector Past Perfect Simple…Would/Could/Should/Might have + Past Participle…
If you had stayed out that night, you would have felt very tired the next morning.
Impossible Conditional: we refer to past actions that can not already be changed and present a new situation to express what would have happened that way.

3. CONDITIONAL SENTENCES
Other conditionals:
Zero Type: Connector Present Simple…Present Simple
If you stay out at night, you feel tired.
We stand out that a general situation will always have the same result.
Mixture of 2nd and 3rd Types:
- Connector Past Perfect…would
If you had stayed out late last night, you would be very tired now.
A new hypopthesis for a past situation would have a different result now.
- Connector Past Simple…would have+Past Participle
If you weren’t organized, you wouldn’t have passed all your exams.
A new hypothesis about an habitual or general present situation would have had a different result in the past.