fifth的复数加s还是es

fifth加s

例句

1、

He lifted the cup for the fifth time this year.

他今年第五次举起了获胜奖杯。

2、

Her mother had just given birth to another child， her fifth.

她的母亲刚又生了孩子，她的第五个孩子。

3、

It's the fifth time that I've been to America.

这是我第五次去美国了。