Spanish language Q&A Forum

Hi, what does A mean here? Can it be omitted and still be grammatically correct? 

Thanks a lot,

Shirley. 

A good, easy read, very well-narrated

Creo que los dos son correctos. Leo online que "a" se usa más en América y "en" es más común en España. Pero en "Love Story" (ejercicio de escribir - A1), se dice "entrar al bar" no es correcto! Solo "entrar en el bar". Porque?

what's the difference between usted and vosotros?

Can I use debo instead of debería? For example: 

I don't feel like there is good guidance in this.  I see what appears to be mixed modes- Mi and ti, but not nos- it's nosotros.  If nosotros is the valid pronoun for this form, why is ti valid and tu not valid? There is no guidance here and I am constantly getting these screwed up.  To me, nosotros=we, nos=us, and nuestra=our.  I get it if they truly use those in that way, but please call it out as an exception so I know to memorize it that way.  Otherwise I am trying to find and fit a pattern and am hitting the wall trying to pass these tests in a way that I know I can replicate this in a week or a month from now and get it correctly then as well, and not just memorize it long enough to pass the test today.

Why are there pronouns attached to the verbs in the first three examples but not in the remaining examples?   

The first and third examples are reflexive (which explains those), but what about the second one ("comerlos")?  Thanks.