a no ser que

a no ser que
 

a no ser que : I think it means even if, but it might mean unless. Can someone clarify this? Thanks.

A no ser que means unless.

Haz esto por mí, a no ser que ya te tengas que ir.
Do this for me, unless you already have to go.

That is. I don't think it's complex to use it, as you can always say a no ser que in the same contexts that in English you would say unless.

Eso es. = That's it. :)

Thanks a lot, David. I was doubtful about it, but couldn't remember this small phrase!

Yo que sé! is an expression I hear always, I suppose it means; what do i know? but I´m not sure.

You are right!
It's also very common: ¡Y yo qué sé!

It implies a certain level of familiarity, so I wouldn't use it in a formal context, Jane.
In my mind it belongs to the sort of expressions my teenage daughter uses all day long:
- whatever!
- as if I cared
- Duh!
When you say ¡Yo que sé! you are implying you want to be left alone.

Hmmm...
:coffeebreak:
Point taken.:cool:

What about what do I know? Does it imply the same as yo qué sé?

What do I know ?is (as far as I know) is ¿Qué sé yo? which I suppose
means ¿yo qué sé?

I think Alfonso is asking a question about register not about meaning. In a certain way,when you say What do I know? you are metaphorically trying to get rid of the person who asked you or to elude responsibility and depending on context and intonation it might not be too polite.:confused::confused::confused:

I agree.......it's as if saying "what do I know" followed by "I'm only the......."

Sometimes when students argue with their teacher the teacher may respond....

"What do I know, I'm only the teacher."

Of course, the comment is usually made with sarcasm.

Thanks a lot you all. It's clear now. I guess what do I know is a common expression as it is qué sé yo, meaning the same, as much semantically as pragmatically (effect on the interlocutor).