Indirect questions with "à"

Question

I am wondering how to translate the following sentence into French:

"Explain to me what you were thinking".

I am assuming here that we are using "penser" with "à", i.e. the direct question here is "à quoi pensais-tu?" (what were you thinking?).

I am not sure as to how to express this as an indirect question. I was thinking along the lines of:

"explique-moi ce auquel tu pensais" or "explique-moi où tu pensais"

But I am pretty sure both of these are incorrect so I would really appreciate some help.

Merci!

Answer 1

Comme le dit le commentaire de aCOSwt: "explique moi ce à quoi tu pensais" serait la forme correcte.

Une autre formulation plus simple pourrait être "à quoi pensais-tu ?".