fillies
n．小母马（复数）：指未满四岁的母马。
例句
There are a few ideas around on how to treat fillies and mares in season.
关于如何对待发情期的小母马和母马有几种观点。
《柯林斯英汉双解大词典》
You should understand: we were fillies and young guys.
你得明白：我们那都是些大姑娘和小伙子。
Throughout the first two years, the bodies of these young colts or fillies will be growing tremendously quickly.
前两年，这些小雄马或小雌马的身体会成长的非常快。
