El mes pasado comenzaron mis vacaciones.
It’s asking, when did Ignacio’s vacation start. And he had said that his vacation lasted 20 days there for about a month ago.
Answer:
Possessive adjectives occur before a noun (my car) or an adjective + noun (my new car). Rule 3. Possessive adjectives have no singular or plural. They are used with both singular and plural nouns (my book, my books).
The correct word in this case is APOYARIAMOS because the conditional form is apoyar-ía, -ías, -ía, -íamos, - íais, -ían