留学は自己を見つめ直すよい機会になった。
Studying abroad was a good opportunity to take a fresh look at myself.
青年期は自己を確立していく大切な時期だ。
Adolescence is an important period for establishing one's sense of self.
貴重品は自己の責任で管理してください。
Please look after your valuables at your own responsibility.
彼は自己を犠牲にしてまで仲間を守ろうとした。
He tried to protect his companions even at the cost of sacrificing himself.