这些文档被设置为只读，所以无法编辑。

These documents are set to ___ro, so they can't be edited.

我正在学习罗马尼亚语，希望明年能去罗马尼亚旅行。

I'm learning ___Romanian and hope to visit Romania next year.

我们安装了反渗透系统来净化自来水。

We installed an ___RO system to purify tap water.