How do you say what are thinking of in French?

There are a few ways to say "what are you thinking of" in French, depending on the context and level of formality:

Formal:

* À quoi pensez-vous ? (Formal, literally translates to "What are you thinking about?")

* Qu'est-ce qui vous vient à l'esprit ? (Formal, literally translates to "What comes to your mind?")

Informal:

* À quoi tu penses ? (Informal, literally translates to "What are you thinking about?")

* Tu penses à quoi ? (Informal, literally translates to "You are thinking about what?")

* Qu'est-ce qui te trotte dans la tête ? (Informal, literally translates to "What's going through your head?")

More specific:

* Tu penses à quelqu'un ? (Are you thinking about someone?)

* Tu penses à quelque chose en particulier ? (Are you thinking about something specific?)

The best way to choose the right phrase depends on the situation and your relationship with the person you are speaking to.