The chief reason for the population growth is_______________________________(与其说是出生率的上升，还不如说是死亡率的下降)．

【参考答案】

not so much a rise in birth rates as a fall in death rates／m......

(↓↓↓ 点击下方‘点击查看答案’看完整答案、解析 ↓↓↓)