old age;ageing 中國(guó)人口年齡已開(kāi)始進(jìn)入～化時(shí)代。The age structure of Chinese population has entered the ageing stage./～工作work concerning the elderly (or related to senior citizens)/～化社會(huì)ageing society/～問(wèn)題ageing problem/～事業(yè)undertakings for the aged