现代写字用的墨水通常包括了硫酸亚铁和少量的酸；写在纸上，颜色会越来越深，且能保持永不褪色。
Modern writing inks usually contain ferrous sulfate with a small amount of an acid; on paper they darken and bond becoming permanent.
有的只是用永不褪色的墨水写下了自己的名字，有的在木牌上刻下名字的首字母，还有的写了留言。
Some had merely signed their names in Everlasting Ink; others had carved their initials into the wood, still others had left messages.
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