be cast in stone直接翻譯是“刻在石頭上”，可以翻譯成“板上釘釘、無(wú)法改變”。
【例句】
These suggestions are for discussion. They are not cast in stone.
這些建議是用來(lái)討論的，不是板上釘釘?shù)摹?br />
These requirements must be met, but as for the way you make it is not carved in stone.
這些要求必須滿足，至于你怎么做不是硬性要求。