求翻译：进入新世纪以来，中国面临的人口再生产状况已经发生了根本变化。中国人口在上世纪50、60年代，由传统的高出生、高死亡、低增长，转变到高出生、低死亡、高增长后，仅仅30年左右的时间，就已过渡到20世纪90年代以来的低出生、低死亡、低增长。而且，出生率下降的趋势基本不可逆转。是什么意思？

Since the beginning of the new century, the population reproduction situation facing China has undergone fundamental changes. Chinese population in the 1950s and 1960s, the by traditional high birth, high mortality and low growth, the transition to the high birth rate, low death rate and high growth

Since the beginning of the new century, China's population situation has been radically changed. China's population in the last century, 50, 60, from the traditional age of high birth, high mortality, and low growth, the transition to High birth, low mortality, high-growth, only 30 % of the time, it

Entering the new century, China's population reproduction situation has undergone a fundamental change. Chinese population in the 50 and 60 of the last century, from the traditional high growth, high mortality and low birth, changing birth after death, high growth, low to high, only 30 years or so o