只有ninth的写法，没有nineth的写法，这个写法是错误的；
ninth
ord.第九；
n.九分之一；
复数： ninths；
例句：
The elevator went up to the ninth floor.
电梯升到了9楼。
It's also called the Double Ninth Festival.
这又叫重阳节。
It is celebrated on the ninth day of the ninth lunar month.
在农历九月初九庆祝。
In Brussels the dollar rose by a ninth of a cent
在布鲁塞尔美元升值了1/9美分。
温馨提示：
