indelible

那次旅行给我留下了不可磨灭的回忆。

That trip left an ___indelible memory in my mind.

这种记号笔的墨水是永久性的，写在白板上擦不掉。

The marker has ___indelible ink that won't wipe off the whiteboard.

烧伤在他前臂上留下了一道无法抹去的疤痕，永远提醒着那次事故。

The burn left an ___indelible scar across his forearm, a permanent reminder of the accident.