- 基数词变序数词
one-->first
two-->second
three-->third
four-->fourth
five-->fifth
six-->sixth
seven-->seventh
eight-->eighth
nine-->ninth
基变序，有规律，词尾加上 th;
一、二、三，特殊记，词尾字母t, d, d;
八去 t, 九除 e, ve 要用 f 替；
ty将y变成i, th 前面有个 e;
若是碰到几十几，只变个位就可以。
It's never too late to be what you might have been.
勇敢做自己，永远都不迟。（乔治·艾略特）
