proportion of old population的用法和樣例：
例句
用作名詞 (n.)
- The proportion of regular smokers increases with age.
習慣吸煙的人口比重隨年齡的增長(cháng)而上升。 - China's population continues to grow,the proportion of the aged is getting larger,and the pressure on employment and social security is mounting.
人口總量繼續增加，老齡人口比重上升，就業(yè)和社會(huì )保障壓力增大。
