Avere/essere
When to use avere, when to use essere in passato prossimo indicativo? For example, -Ho studiato quattro anni la lingua italiana. -siamo venuti dalla Italia. Why we use essere in the second sentence?

Question

Answer

Some verbs require "avere" as auxiliary verb to make compound tenses, some others require "essere".
Usually transitive verbs require "avere" (so you can use "essere" to make passive forms), intransitive verbs require "essere", but this is not a rule. You have to remember, or take a look at dictionary, which is the right one.