Time for a question! In the fourth book there was mentioned that cho is one of the fith 年 girls, but then suddendly in DH she is back at Hogwarts. What do あなた think happened? Did she came back to help または failed her examens?
Do あなた think she decided to stay at Hogwarts because she wanted to help Harry?
Since she was a member of Dumbledore's Army back in Order of the Phoenix, she could have been summoned for the fight as long as she'd kept her Galleon. That's how all the older students who'd left Hogwarts によって that 年 knew to return (other than Oliver Wood, who'd left before OOTP, so someone from Gryffindor must have contacted him).
