<Li> Traditional age, "virtual age" (traditional Chinese: 虛歲 / 齡; simplified Chinese: 虚岁 / 龄; pinyin: xūsuì / líng) based on the East Asian reckoning system </Li> <Li> Modern age, "round age" (traditional Chinese: 周歲; simplified Chinese: 周岁; pinyin: zhōusùi) </Li> <Li> "Solid age", (traditional Chinese: 實 歲; simplified Chinese: 实 岁; pinyin: shísùi) based on the Gregorian calendar </Li> <P> Of the three, only 周歲 / 周岁 (Chinese), zhōusuì (pinyin) = "round age" may be used as a count word . </P>

When does a baby turn one years old