Unos/algunos
 

I know they both mean some, but they cannot be interchangeably in many cases. Are there rules for their use?

That's a good question poli. :D
I think that "algunos" can be more vague than "unos". :thinking:

Mmm... I don't know. From my perspective, they aren't interchangeable just when "algunos" means "certain" (ciertos). For everything else, I think they are. However, to me, "unos" is more imprecise: "unos" can be "dos" but "algunos" is always more than two.

A pleasure.

OK, that's the answer! In English certain and some can be interchanged a in certain characteristic/some characteristics, but in Spanish, it's best to use algunos.

Personally, I think when in doubt, use algunos.

This is tricky... I've spent a couple of hours reflecting on this and I'm still not sure I can offer a clear explanation, but here I go:

When the purpose of the things referred to as "unos" or "algunos" is clear, then they're perfect synonyms:

- Compré unas/algunas naranjas para hacer jugo.
- Tengo unos/algunos vestidos que quiero regalarte.
- Sobre la mesa hay unos/algunos libros que te van a encantar.


When the idea of "some" is opposed to "all", then "algunos is preferred:
- Vinieron algunos señores del grupo a buscarte. -> Only a part of the group, not all of them, but not just "any".
- Llegaron algunos de los invitados a la fiesta. -> Not everyone who was invited came to the party.
- En la visita al aviario, apenas vimos algunos pájaros. -> We didn't see as many birds as there were in the aviary.
- Algunos calendarios no traen las fases de la luna. -> Some calendars, not all.



And there is this fuzzy difference when "algunos" tends to be a little more specific than "unos":
- Juan me dio unos dulces. -> I just received some sweets from Juan.
- Juan me dio algunos dulces. -> If I say this, then my reader and I must know that Juan had sweets and he shared a few of them with me.

- Compramos (unas) naranjas. -> We just bought oranges.
- Compramos algunas naranjas. -> We bought some specific oranges from a place or a kind that we already knew.



When the idea is opposed to "ninguno", then "alguno" is preferred. (In this case, I can only think of the singular, never the plural):

- ¿Alguien tiene alguna idea de cómo salir de aquí?
- ¿Tienes alguna pluma en tu bolsillo?


:thinking: