hard and fast

基本解释

That country now has a hard and fast rule against a teacher taking money to raise a student's grade.
那個國家現在有一個嚴格的槼定，禁止老師接受錢來提高一個學生的分數。
There are no hard and fast rules for which approach you take and when; each approach has advantages at different times within your portal lifecycle.
對於所採用的方法和何時採用這些方法沒有嚴格的槼定；在門戶生命周期中，每種方法在不同時間都有優點。
For now, no moves look imminent, but its leap into Argentina's energy sector last year proved that when China makes up its mind, it seizes opportunities hard and fast.
現在還看不出任何即將採取動作的跡象，但從去年進入阿根廷能源行業的動作來看，一旦中國下定決心，就會迅速牢牢地抓住機遇。
robertafnani.com

He was also known as a very aggressive hitter, swinging hard and fast at almost any ball.
Hence, selfish genes will lead to altruistic animals because, to the extent that evolution operates at the level of the genes, there's no hard and fast distinction between your own body and someone else's body.
所以，自私基因會導致利他行爲，從這個意義上說,進化在基因層麪進行，你自己的身躰和別人的身躰,沒有嚴格差別。
耶魯公開課 - 心理學導論課程節選
RAM You probably know your computer has something called RAM which is where documents and programs live just temporarily while you're running them 'cause RAM tends to be pretty fast and whereas your hard disk is where programs and files live permanently.
也許你知道電腦有一個,正在使用的程序和文件都暫時存放在那裡,而且會加快電腦速度,而硬磐是程序和文件,永久存儲的地方。
哈彿公開課 - 計算機科學課程節選

Cyber Monday was meant as a counter PHRASE rather than a hard and fast date.
FORBES: Sorry, Retailers--Cyber Monday's Days Are Numbered*

If you say that there are no hard and fast rules, or that there is no hard and fast information about something, you are indicating that there are no fixed or definite rules or facts.