Second Conditional
Refers to a hypothetical situation and the structure is formed as if + simple past + Simple conditional. Here are some examples translated. 

If clause	Main clause
If + Past Simple	would / could / might + verb
If I won the lottery,	I would travel around the world.

• 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.
• If I had more money, I would buy a nice apartment.
  Si yo tuviese más dinero, me compraría un lindo apartamento.
• If she had more time, she would travel more often.
  Si ella tuviera más tiempo, viajaría más a menudo.
• If it were not raining, we could go out.
  Si no estuviese lloviendo, podríamos salir.
• If we didn't have to work today, we could have a picnic.
  Si no tuviésemos que trabajar hoy, podríamos tener un picnic.