I know “B sold here” is the right form. But I don't know why it's the right form instead of “B sells here”?
Could someone (e.g. @Mistu4u) with enough rep to create the tag please tag this with passive-voice (and maybe copy the tag wiki from english.SE while you're at it)?– Ilmari KaronenFeb 17, 2013 at 11:54
"B sold here" is a passive construction that means "We sell B in this shop" (active) => "B is sold in this shop by us" (passive) => "B is sold here" => "B sold here". "B sells here" is not normal or idiomatic for this expression.
It is normal and idiomatic to use the active voice present progressive when talking about the level of sales, however, as in "B is selling nicely in our American stores but not in our Mexican stores". This is just the way we use the language. There may be some technical linguistic explanation for this kind of transmogrification from passive to active, but I don't know of one.
4A verb which allows the object in one clause to become the subject in another is an ergative verb. Feb 17, 2013 at 12:15
B sells here
That construction is ambiguous because "B sold here" means "an unspecified person/entity sells an object B in this place," while "B sells here" means "the person/entity B is selling an unspecified object in this place."
4More than ambiguous, I would say that "B sells here" has a different meaning than "B sold here."– apadernoFeb 17, 2013 at 14:29
@kiamlaluno: I used the word ambiguous because it is still possible for it to be interpreted in passive sense, as in "B sells (well) here". But that's probably a different meaning, as you said.– Lie RyanFeb 17, 2013 at 16:24