Quindecennial
十五年期間\\na. 每十五年發生一次的, 持續十五年的
??? 情景例句
Relax! Be patiend and enjoy yourself.
放松點！要有耐心，并讓自己快樂！
I asked him to stop, but he wouldn't.
我請他停止，但是他不肯。
Yes. I wouldn't go home early if I were you.
是的，如果我是你，我不會早回家。