Universal truths are constant, it's a fact, a plain and simple fact that what is true and right for all.
1. Universal truths 普遍真理
Universal [junvrsl] adj. 普遍的； 全體的； 全世界的； 共同的； 普遍存在的
it's a truth universally acknowledged that……
此及放之四海皆標準的道理……
2. it's a plain and simple fact that……
Plain and simple 簡單明了， 平淡樸素
Plain and simple clothes are appropriate for school wear
樸素的服裝適合在學校裡穿
Don't beat around bush, state you case in plaim and simple terms
不要拐彎抺角，用平凡簡單的話語直接闡述你的觀點
3. for all=for good/for good and all 永遠， 徹底
And then, he felt for good 就這樣，他徹底離開了
When John graduated from school, he decided that he was done with study for good and all.
約翰從學校畢業時， 決定永遠不再與學習打交道了
拓展，once and for all 斷然的，一次性的，徹底的
i am going to settle this matter once and for all
我要徹底解決這個問題
Heared from the Maltese Riviera, once and for all
去馬爾他的，一勞永逸
It was time to put and end to all this once and for all
是時候估徹底的了解了