这些老照片经过精心保存，看起来和新的一样。

The old photos look as good as new thanks to careful ___preservation.

他坚持锻炼以保持健康。

He exercises regularly for ___preserving his health.

她正在用盐腌鱼来保存海鲜。

She is ___preserving the seafood by salting the fish.