Five years old Five - years- old要是中文是五岁的话,哪个对应该是Five years old 还应该是Five - years- old

five years old 或者 five-year-old

中间不应该有 - 的。直接five years old

I am five years old.
I am a five-year-old boy.

前面的

five years old 正确
five-years-old 错误,当有连字符号时,要把s去掉.而且后面还要有名词.
如：She is a five-year-old girl.

Five years old 五岁 名词
Five - years- old 五岁的 形容词
He is five years old.他五岁。
He is a five-year-old boy.他是个五岁大的男孩。