如何获得包含特定单词的整句？

I want to get whole sentence and paragraph by finding word. For eg: If I search "released" in text "Hundreds of political prisoners have been released, and censorship rules have been relaxed. The EU and US have lifted the majority of sanctions against Burma as a result. " it should to return "Hundreds of political prisoners have been released, and censorship rules have been relaxed." and whole paragraph as well. I want to get whole sentence and paragraph by f