But I think I got it. Here it is, because it's just so damned cool. =)
Some verbs take être instead of avoir (French) or essere instead of avere (Italian) to form the past tense. Nutty little mnemonics like "Mrs. D. R. Vandertramp" may or may not be effective, but for me, there's really no substitute for understanding the true reasons as to why things are the way they are.
- The agent of a verb is the person/place/thing/idea that is performing the action that the verb is expressing.
- The theme of a verb is the person/place/thing/idea that is undergoing change related to the verb. It could be a physical change or some kind of state change.
- The recipient of a verb is the person/place/thing/idea that is receiving the action that the verb is describing.
These are not the same as the subject, direct/indirect objects and verb complements. Those can be different depending on how you craft your sentence. For example, these two sentences:
|Mary||gave||the gift||to Bob.|
|The gift||was given||to Bob||by Mary.|
But in both of those examples, the verb is "to give", the agent is "Mary", the theme is "the gift", the recipient is "Bob". No matter how you rephrase it and rearrange the different components, the agent, theme and recipient will always be the same. The syntactic roles are different from the semantic roles. We have the ability to express things any which way.
If the agent, theme and recipient of a verb are either unclear or two of them are the same, then the past tense is formed by using the verb "to be" as the auxiliary plus the past participle.
That's it. That's all there is to it. This is true for French and Italian. I'm betting it's true for many Romance languages.
This is why verbs that express movement are in this category (leaving, coming, going, dying, etc.); the agent and the theme are the same. This is why intransitive and reflexive verbs will always take "to be" to form the past tense.
I'm not sure why this is not formally taught... maybe it was just my luck of the draw with the teachers I had. I would have had an infinitely easier time remembering if I knew WHY those verbs always took être/essere to form the past tenses. It's much harder to forget and harder to get it wrong when you derive it from the original principles like that.