Answer:
The sentence that we have here is:
Tú estudias.
Where the person is "Tú" and the verb, already conjugated in the present tense, is "estudias", and the verb non conjugated is "estudiar".
So now we want to conjugate "estudiar" in the preterite tense where the person is "Tú"
This would be:
Tú estudiaste- in the perfect preterite.
Tu estudiabas- in the imperfect preterite.
