AnalyzerSentence analysis3SpansSentence空洞にする1000 character limitAnalyzeSentence空くう洞どうにするSpan Details空くう洞どうcavity; hollow; cavern; cavernousnoun, no-adjectiveにdirection, time, indirect object, or target markergrammarするlight/support verb with a noun or noun-like phrasegrammar