凶兆の廃墟
土地
凶兆の廃墟が戦場に出るに際し、あなたの手札にあり沼や山であるカード１枚を公開してもよい。そうしないなら、凶兆の廃墟はタップ状態で戦場に出る。
：
か
を加える。
イラスト：
The Lost Caverns of Ixalan Commander#330レア日本語適正
裁定
If an effect instructs you to put Foreboding Ruins onto the battlefield tapped, it will still enter the battlefield tapped even if you reveal a land card from your hand.
Lands don't have a subtype just because they can produce mana of the corresponding color. Foreboding Ruins itself is neither a Swamp nor a Mountain, even though it produces black and red mana, so you can't reveal one to satisfy the ability of another.
If a Swamp or Mountain is entering the battlefield from your hand at the same time as Foreboding Ruins, you may reveal the other land to have Foreboding Ruins enter untapped.
You may reveal any land card with either or both of the appropriate subtypes. It doesn't have to be a basic land. For example, you could reveal Sunken Hollow from the Battle for Zendikar set to satisfy the ability of Foreboding Ruins.