Where "would" = the conditional Here, then, are the major usages of the conditional that can be understood by using the English "would":
Describing an act that depends on a condition: Another way of putting this is that the conditional indicates the possibility of an action related to specific circumstances. The circumstances (that is, the condition) can be stated, but they don't have to be. Note the following examples, with the conditional verb in boldface:
Si tuviera dinero, iría al cine. If I had money, I would go to the movies. (The condition is having money. In this case, the condition in Spanish is stated in the imperfect subjunctive, as is very common. It is also stated in the subjunctive in the English sentence, and this is one of the few constructions where the subjunctive form is still used in English today.)
Yo comería la comida, pero soy vegetariano. I would eat the meal, but I'm vegetarian. (The condition is being a vegetarian.)
María habría venido, pero su madre estaba enferma. Mary would have come, but her mother was sick. (The condition is her mother's sickness. This sentence is in the conditional perfect form, using the conditional tense of haber followed by the past participle.)
María habría venido. Mary would have come. (This sentence is the same as the one above, but without the condition explicitly stated. The condition would have to be inferred from the context.)
Con más dinero, yo ganaría. With more money, I would win. (The condition is having money. This is a case where a condition is expressed without using si.)
Yo no hablaría con ella. I wouldn't talk with her. (The condition is unstated, but it could be something such as si fuera tú, "if I were you.")
In a dependent clause following a main clause in the past tense: In such cases, the conditional tense is used to describe an event that might have happened after the event in the main clause. A few examples should help clarify this usage:
Dijo que sentiríamos enfermos. He said that we would feel sick. (In this case, feeling sick happened, or might have happened or will happen, after he made his statement. Note than in such a sentence construction, the que, or "that," doesn't always have to be translated into English.)
Supe que yo saldría. I knew I would leave. (As in the above sentence, the act of leaving isn't connected to a specific period of time, except that it takes place, or could take place, at some time after the knowing.)
Me prometió que ganarían. She promised me they would win. (Again, we can't tell from this sentence whether they actually won, but if they did it came after the promise.)
To politely make requests or state desires: The conditional can be used to sound less blunt.
Me gustaría salir. I would like to leave. (This sounds gentler than Quiero salir, "I want to leave.")
¿Podría obtener un coche?Would I be able to obtain a car?
Note that querer in the subjunctive is sometimes used in a similar way: Quisiera un taco, por favor. I would like a taco, please.