Mio padre ha avvitato la lampadina senza usare la scala.

In Italian, when you refer to a singular, unmodified family member with a possessive adjective, you normally omit the definite article.

• Correct: Mio padre è arrivato.
• Wrong: Il mio padre è arrivato.
  If you add an adjective or extra clarification (e.g. il mio caro padre, il mio padre biologico), the article returns.

Ha avvitato is the passato prossimo (present perfect), used to describe completed actions in the past. It’s formed by:

1. The present-tense auxiliary avere (here ha)
2. The past participle of the main verb (avvitato)
   So ha avvitato = “has screwed in” (i.e. “screwed in”).

Avvitato is the past participle of avvitare, which means “to screw in” or “to fasten by turning.” Common uses:

• Avvitare una lampadina (“to screw in a lightbulb”)
• Avvitare un bullone (“to screw in a bolt”)
• Avvitare il tappo (“to screw on a cap/lid”)

Using la lampadina implies you’re talking about a specific bulb already known in context. If you wanted to introduce it for the first time or speak generically, you could say una lampadina:

• Mio padre ha avvitato una lampadina (a bulb, any bulb)
• Mio padre ha avvitato la lampadina (the particular bulb we mentioned)

Replace la lampadina with the direct object pronoun la placed before ha:

• Mio padre l’ha avvitata senza usare la scala.
  Here, avvitata agrees in gender and number because la (feminine singular) precedes the auxiliary.

To express “without doing something,” Italian uses senza + infinitive:

• senza + usare (without using)
  Then you add the object of the infinitive (la scala). You cannot insert the article or object before senza itself.