I have learned a lot from this book (많은 생각이 들었다->많은 것을 배웠다로 ..이왕이면..독후감같은 내용이니까요)

People can achieve anything by teamwork. (교훈이란 말 앞 문장에서 써서 두번째 문장에선 생략)

Therefore I learned that I should solve some of my problems with a team.

I have learned that one should not judge the book by its cover from reading this book.

(영어에서는 '겉만보고 판단하지 마라'라는 속담을 '책의 겉표지로 내용을 판단하지 마라'로 '책'을 인용해서 쓰입니다)

I reflected upon my past misunderstandings judging the people by its looks and told myself that I would never do it again.