Set in stone
1. To be very difficult or impossible to change.
The schedule isn't set in stone, but we'd like to stick to it pretty closely.
2. no longer changeable; "the agreement is not yet set in stone"
unchangeable - not changeable or subject to change; "a fixed and unchangeable part of the germ plasm"-Ashley Montagu; "the unchangeable seasons"; "one of the unchangeable facts of life.
Ulasan
Catat Ulasan