his/her/your theory
La sua teoria è difficile da capire.
His theory is difficult to understand.
È difficile comprendere la sua teoria.
It is difficult to understand his theory.
Vale la pena considerare la sua teoria.
His theory is worth considering.
Zamenhof mise in pratica la sua teoria.
Zamenhof put his theory into practice.
Non c'è tempo per approfondire la sua teoria.
There isn't time to delve deeper into his theory.
— Il quinto elemento (1997)
Tell him your theory.