교과서본문에서 문법이 걸리는게있어서요..

later, i came to work as an official three times, but each time i was fired from ( the office/office )
이문장에서 왜 the office 를 쓰면안되는지와

my parents gave girth to me, but ( it/that ) is bao who really understands me
이문장에서 왜 that이안되고 it 을 써야하는지가 궁금합니다!!ㅜ.ㅜ

그리고

it is said that damon and pythias impressed even one of the most motorious kings, dionysius 1 of syracuse
밑줄부분을 바꾸는 문법문제인데

→damon and pythias

빈칸의 답으로 damon and pythias are better known for impressing 이 맞는가요?