洞 is one of the most commonly used Japanese kanji, and it also has a lot of special readings in addition to the standard onyomi and kunyomi readings.
ONYOMI 音読み
ほら hora
KUNYOMI 訓読み
ドウ dou
Examples
ほら、あなたの乗る電車が来たわ。Look, here comes your train.ほら財布だ。Here’s my wallet.ほら!台所に猫がいる。Look! There’s a cat in the kitchen.ほらね、雨が降っているよ。It is raining, you see.ほら!あの木に小鳥がいる。Look! There’s a bird in that tree.ほら、お母さんが来られたよ。Look, here comes your mother.ほら、始まるわよ。It’s starting now.ほら彼女がいますよ。Here she is!ほら、彼女がやってくるよ。There she comes.ほらバスがきましたよ。Here comes the bus!