"I have met two doctors."
Translation:Yo he conocido a dos doctores.
The personal a is not used when you are talking about non specific things or people. I suppose you can say that this is not specific, as you only have met two doctors out of the entire world's supply of doctors.
I might be slightly off the mark but this could be a reason why.
The "personal a" is not needed and seems wrong to me.
EDIT: OK, I can see the logic in KenHigh's comment and that justifies the use of "a " here. If the speaker is not referring to specific doctors, however, the "a " is not used. So, it depends on the speaker's intent.
According to "A New Reference Grammar of Modern Spanish":
Nouns preceded by a number may be unspecified or unidentified and personal a is sometimes omitted before them. Reclutaron (a) doscientos jóvenes - They recruited 200 young people.
A clearly particularized or identified personal noun will, however, take personal a: yo conocía personalmente a sus tres hijas ‘I knew his three daughters personally
I think I can imagine a situation when I talk about two unspecified doctors (as opposed to three, for example).
But as well as "Nunca lo he conocido a él", we also had "Algo le ha pasado a mi coche", where surely "mi coche", being explicit, should obviate the need for the IO pronoun "le".
Admitedly, coche is inanimate and "haber pasado a" may work differently from "haber reconocido a", but I am still confused.
In your second example coche is an indirect object. Indirect object pronouns are always used with or without a named direct object. Direct object pronouns are generally not used with a named direct object. You will find they are used by some native speakers sometimes, which is what you saw demonstrated. Personally I do not feel comfortable enough in my understanding of this usage to do it myself, but I am aware enough to understand it when I see it.
I don't know the easy answer to this, so I'll give you the long answer.
Since the indirect object pronoun (IOP) is used more than the direct object pronoun (DOP) in regards to people, I will add "Les VERB a Pronoun" to your list. Also, you can often drop the "a PRONOUN" when the context has already made the object pronoun clear (lo, la, los, las, le, les.) And my answer is a tentative YES. I would argue that "Les VERB a NOUN" isn't incorrect; it's simply redundant.
This logic has worked for me with duolingo, however there are a lot of examples which break the rule.
Examples that work for the rule:
le lee un diario
Yo les leo un libro
puedo observar a mi amigo
Oí a tu padre hablando en la radío.
Lo vamos a seguir a usted.
Ellos le leen una revista a ella.
Yo le leo un periódico a él.
Yo leo las palabras.
veo a un hombre.
ella lo ve a él.
El jugador dio el balón al árbitro. (wordreferenc.com - Dar)
pregúntale a cualquiera.
puedo hablarle a mi doctor
le puedo hablar a mi doctor
les tiraban piedras a los soldados. (wordreference.com - Tirar, collins tab)
Also, sometimes an object pronoun is added to make clear that the first word is an object instead of a subject:
Este tema lo veremos en la próxima clase. (wordreference.com - ver, collins tab)
we'll be looking at this subject in the next lesson.
Esto lo tiro yo.
I throw this.
Examples are taken straight from duolingo unless cited, so you can find them by searching in the discussion section.
If you find a definitive grammar rule which explains all this, please share it with me.
Because the direct object "doctores" is a noun, and your example uses a pronoun, "lo", as the direct object.
To be more specific, for masculine pronouns, "él" is used as a subject pronoun and a prepositional object pronoun, while "lo" is used as a direct object pronoun. So, in your example, the direct object pronoun "lo" is used for "Nunca lo conocido." (And yes, the placement of the direct object changes for pronouns versus nouns.) However, since "lo" can be either masculine or neuter, we can optionally qualify it with a prepositional phrase, using the prepositional object "él" to give us "Nunca lo conocido a él."
Present perfect is just the present tense of HABER (conjugated) + the past participle of the desired verb, e.g. He corrido, has sentado, hemos conocido (I have run, you have sat, they have known/met). You can use the present perfect with reflexive verbs (e.g. irse--to leave): Me he ido. With reflexive verbs, place the reflexive pronoun before the conjugated form of haber has the haber+participle combo must be kept together.
The personal a is not a normal preposition. It known as a morphological marker, in other words, a little thing that is added because of grammar rules, that also helps one to understand the various parts of a sentence. In Spanish, the personal a is required before a human direct object, or other affectionate beings such as pets. What follows the personal a, is still a direct object, not an object of a prepostion.
Having the personal a before a direct object, among other things, helps a reader or a listener to know who is the subject of a sentence and who is the object. This is necessary in Spanish which unlike English, normally requires a SVO Subject Verb Object order, the sentence order in Spanish can be much more flexible.
In other words....
Maria vio Juan.
Maria saw Juan is the only meaning of this in Englsih.
In Spanish, it could mean Juan saw Maria.
Except in reality, this sentence is illegal because either Juan or Maria has to have a personal a in front.
A Maria la vio Juan.
Can only mean Juan saw Maria.
Maria vio a Juan.
Can only mean Maria saw Juan.
No, I completely disagree. Past tense of "tener" in first person is tuve.
The reason why this is haber is because in English "have" is an auxiliary verb, which means it can be used as a doing (or lexical form such as run or eat) and a grammatical verb (or modal such as must or should).
For example. "I have a dog". In this case you are doing the action of owning a dog. If you replace "have" with another verb such as "love" and it makes sense, you use tener.
With haber, it is used modally, which means it's only there for grammatical reasons, and are used for obligation (must), possibility (may) and ability (can).
To find out if you use haber vs tener, try replacing the English equivalent with another verb. "I have had a dog" goes to "I love had a dog". In this case you use haber.
If you are still confused, look up auxiliary verbs on Google.
Tener means have as in to possess, but it is not the have which is the auxiliary verb for the perfect tenses. That is Haber. Haber is a strange verb as the only time it is fully conjugated is as an auxiliary verb. The only other use of Haber is that the third person singular is used to mean there is or there are. Of course hay is also mutated in the present tense. But I have met, I have seen, I have done all use Haber He conocido, he visto, he hecho.