Sorry, per.fagrell, The only reason for the "a" in "al perro" is because the dog is an animate object, a pet. It needs the "personal a". In the example, horse is not an indirect object. It's the object of a preposition.

So it seems the answer is that one is that "al" applies to predicate objects and "del" applies to prepositional objects (in the case that it follows verbs and isn't possessive of course).

Hi, Oddible. There's a grammatical elephant in the room that no one has noticed: the use of "del" here has nothing to do with the verb. Rather, it's because the preposition "cerca" carries the preposition "de" when it's followed by something else. E.g., "El caballo está cerca," but "Estoy cerca del caballo." Consider this: "Veo al caballo cerca del perro."

AL is a contraction for "a el" (but not for "a él"), so it means "to the". DEL is the contraction for "de el", so it means "of the". In the case of "No veo al perro", we use the contraction because of the personal "a". You would say "no veo el carro" (no personal "a").

The dog is the direct object, and the horse is the indirect object. I think that's why you use 'a' in the first and 'de' in the second example. I see over to the dog, but the dog is walking in the vicinity of the horse is what it sounds like in my head. :)

CalvoViejo: so the only reason for 'del' instead of 'al' in the second sentence is that the horse isn't a direct object? I'm pretty sure a horse is animate, so there must be some difference, right?

Wrong again, Aadit. "Del" is a contraction of "de + el". It does mean "of the" or "from the", but is NOT a contraction of "de + la". There is no contraction in Spanish involving "la".

Per: if we don't use the "personal a", the two example sentences would be: "no veo el perro" and "camina cerca del caballo". I don't want to get too technical, but "ver" is a transitive verb; it requires a direct object. "Caminar" is intransitive; it cannot have a direct or indirect object. When a direct object is a person or is an animal and we have some feelings for that animal (as in a pet), we use the personal "a", so, in our example, "el" becomes "al". We don't use the personal "a" with prepositional objects.

CalvoViejo: Thank you for the grammatical explanation of the use of 'de' in the second sentence.

oddible: the word 'a' is appearantly filled with meanings, not all obvious to an english speaker; I found a summary of it's uses here: http://spanish.about.com/od/prepositions/a/a.htm