That day is stamped indelibly on my memory.

那一天在我的脑海中留下了不可磨灭的回忆。

The terrible scenes were indelibly imprinted on his mind.

那些恐怖场面深深地铭刻在他的心中。

The memory of that day was indelibly printed on his brain.

那天的记忆永不磨灭地深印在他的脑海里。

The horrors he experienced are imprinted, perhaps indelibly, in his brain.

他经历的恐怖事件在他脑海中刻下了深深的，也许是难以磨灭的印记。

To fix deeply or indelibly, as in the mind.

牢牢记住：在心中根深蒂固地记住。