set in stone
US /sɛt ɪn stoʊn/
UK /sɛt ɪn stoʊn/

1.
板上钉钉, 不可更改
fixed and unchangeable
:
•
The decision is not yet set in stone, so we can still make changes.
这个决定还没有板上钉钉,所以我们仍然可以做出改变。
•
His plans for the future are set in stone.
他对未来的计划已经板上钉钉。
板上钉钉, 不可更改
fixed and unchangeable