Et toi, ________ as-tu rencontré?

Question

I had this example. Why "Et toi, qui est-ce qu' as-tu rencontré?" is wrong? Can't we use qui est-ce que here?

Accepted Answer

Minas, 
Have a look at the linked lessons. Verb inversion is not used in questions using est-ce que, so using it is not an option in this example.
https://progress.lawlessfrench.com/revision/grammar/how-to-ask-questions-with-qui-que-quoi-quand-ou-comment-pourquoi-and-combien
 https://progress.lawlessfrench.com/revision/grammar/three-simple-ways-to-ask-yes-no-questionsintonation-est-ce-que-nest-pas

Answer

You have to choose between the two options:(1) Qui est-ce que tu as rencontré? -- using est-ce que...(2) Qui as-tu renctontré? -- inversionYou can't use them both in one sentence.