"感谢二十岁" 用英语可以说作 "Thank you for your 20th birthday"。

这句话的来源是表示对某人过生日的祝贺。在英语中，我们通常会在 "Thank you" 后面加上一些具体的信息来表示对某件事的感谢。例如，如果你想表示对某人送给你生日礼物的感谢，你可以说 "Thank you for the birthday gift"。

下面是一些使用 "Thank you for your 20th birthday" 的例句及其中文翻译：

"Happy 20th birthday! Thank you for your 20th birthday." (生日快乐！感谢二十岁。)
"I can't bepeve you're already 20 years old. Thank you for your 20th birthday." (真不敢相信你已经二十岁了。感谢二十岁。)
"Thank you for your 20th birthday. Here's to many more years of happiness and success." (感谢二十岁。祝你更多幸福和成功的岁月。)