"I am going to think about you."

Translation: Je vais penser à vous.

[Ricky_Evans1611]

Why not tu instead of vous?

[MichelLemoine123]

"Je vais penser à toi." is accepted.

[WendyMcInt3]

just discovered that "tu" becomes "toi" after a (grave)

[ksc3j]

exactly! Why not indeed?

[PeterYibo]

that's what they all say

[SharonStad]

Ha ;)

[mrgundrum]

"Je vais vous penser?"

[Jojo553168]

No, penser is usually followed by an indirect object, and uses the prepostion à.

[mrgundrum]

Great, thanks!

[Brian18413]

Would not ABOUT YOU be: je vais penser à ton sujet

[ElizabethM991486]

Oops! I think that only vous works here because "vous" can be both subject and object, but "tu" becomes "toi" when it is the object.

[MaryPaiero]

I was marked wrong for leaving out a space between penser and à. 1 so was marked wrong. On other occasions Duo has allowed little lapses

[RuthChinch3]

Why not "Je vais te penser"? There is nothing after penser...