20岁英语怎么说

20岁英语是"twenty years old"。这个短语来源于拉丁语，在拉丁语中，"twenty"是"vingt"，"years"是"annus"，"old"是"vetus"。"vingt annus vetus"经过英文的转换，就成为了"twenty years old"。

例句：

She is twenty years old.
He will be twenty years old next year.
I was twenty years old when I graduated from college.