radioactivityKK [ˋredioˏækˏtɪvəˏti] /ˈɹeɪdioʊˌækˌtɪvəˌti/發音名詞1放射性Scientists measured the radioactivity of the soil near the old plant.科學家測量了舊廠房附近土壤的放射性。2放射線、輻射Radioactivity in the area has fallen to safe levels.該地區的放射線已降到安全範圍。