The age dependency ratio - the ratio of the young and the aged to people of age 15 to 64 - dropped from 438 per 1000 in 1987 to 398 per 1000 in 1997.是什么意思_The age dependency ratio - the ratio of the young and the aged to people of age 15 to 64 - dropped from 438 per 1000 in 1987 to 398 per 1000 in 1997.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句