Complex sentence: In addition, the possessive version of the non-sentient pronouns is the same as that of who: "whose" takes this role for all of them; e.g., "I will have to fix the car whose engine I ruined".
Split into simpler sentences: In addition, the possessive version of the non-sentient pronouns is the same as that of who: "whose" takes this role for all of them. E.g., "I will have to fix the car whose engine I ruined".