The correct answer is estuviste because it’s in the past.
"Servir" means to work/ function.
"Pedi" means you asked something.
Power is the same thing as it would be in English.
Prober? Maybe you meant "probar" which means to try something.
"Preferir" means to prefer something.
10. Sabemos
12.Conoce
13. Sé
14. Conozco
15. Se
16. Sabemos
17. Conoces
18.Conozco
19. Saben
20. Conoce
21. Sabe
22. Sabe
23. Sabemos
24. Conozco
25. Saben
