彼は単位が足りなくて留年した。
He was held back a year because he didn't have enough credits.
このままでは留年が決まってしまう。
At this rate, I'll end up having to repeat the year.
彼女は留学のために一年留年することにした。
She decided to stay back a year in order to study abroad.
留年しないように、試験前は毎日図書館で勉強した。
I studied in the library every day before the exams so that I wouldn't have to repeat the year.