"The longer the birthinterval, the less likely that the second fetus will be born alive," Lindburg said. "We are simply letting nature take its course."
林德伯格说:“生产间隔时间越长,第二胎成活的可能性就越小,我们只能听天由命了。”
2
Methods The statistical description of fertility rate, age at first marriage, age at first birth, interval between marriage and first birth, birthinterval.
方法应用描述性统计方法分析生育率、初婚初育年龄、婚育间隔、生育间隔和出生性别比及其变化趋势。
3
There is no cure for birth and death unless to enjoy the interval.