Breakdown of ¿Por qué volviste a apretar ese tornillo oxidado?
ese
that (masculine)
por qué
why
oxidado
rusty
apretar
to tighten
Questions & Answers about ¿Por qué volviste a apretar ese tornillo oxidado?
How does volviste a apretar translate to "did you tighten... again"?
Could I just say ¿Por qué apretaste ese tornillo otra vez? instead?
Yes, you absolutely can! Using otra vez or de nuevo (both meaning "again") is perfectly fine and means the exact same thing. However, native speakers use volver a + infinitive constantly, so it is a very important structure to master.
I remember apretar being a stem-changing verb. Why isn't it spelled "aprietar" here?
You are right that apretar (to tighten/squeeze) has an e to ie stem change when conjugated (for example, "I tighten" is yo aprieto). However, stem changes never happen in the infinitive (the dictionary form ending in -ar, -er, or -ir). Since the volver a structure requires an infinitive, apretar stays exactly as it is.
Does the adjective oxidado come from a verb?