Ingles

If + Past Simple would / could / might + verb
• 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 goto 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 wouldtravel 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, wecould have a picnic.
Si no tuviésemos que trabajar hoy, podríamos tener un picnic.
• If they won the lottery, they wouldn't work any more.
Si ellos ganaran la lotería, no trabajarían más.
• If Isaw her, I would ask her out.
Si la viera, la invitaría a salir.
• If you went to Brazil, you wouldn't want to come back.
Si fueras a Brazil, no querrías regresar.
• If they spoke Spanish, wewould understand them.
Si ellos hablasen español, los entenderíamos.
• If he didn't live by the river, he couldn't go fishing.
Si el no viviera cerca del río, no podría ir a pescar.
• If I didn'twant to go, I would tell you.
Si no quisiera ir, te lo diría.
• If they worked for that company, they might have better salaries.
Si ellos trabajaran para esa compañía, podrían tener mejoressueldos.
• If she wrote a book, it would be a best-seller.
Si ella escribiese un libro, sería un best-seller.

El second conditional se usa para condiciones irreales, imposibles, improbables, etc.Hablamos siempre de condiciones que se dan en estos momentos y no de algo que sucedió o pudo suceder en el pasado.
Para que lo veáis claro, miremos un ejemplo:

If I had a lot of money, I would buy a...