birth replacement rate人口置换率
birth control rate节育率
birth sex rate出生性别比
birth stable rate稳定出生率
birth defect rate出生缺陷发生率
birth-rate出生率;翻译
low birth-rate低生育水平
Birth defects rate出生缺陷率
birth h rate人口出生率;出生率;再生速度
N-COUNT（可数名词） The birth rate in a place is the number of babies born there for every 1000 people during a particular period of time. 出生率
America's birth rate fell to a record low last year.
美国去年的出生率降到了创纪录的最低点。