题目内容：

英语翻译
generally believed that the chief reason for the increase in population in developed countries is not so much the rise in birth rates as the decline in death rates as a result of the improvement in medical care.

优质解答

not so much as,not even,never so much as,without even和without so much as这5个词组的意思相同,都为“甚至连…都没有”,\
但是,not so much．．．as却与此不同,
意思是“与其说…还不如说”的意思,一定要区分这两个,原来学英语的时候经常考到.

所以这句话是说： 大家普遍认为的人口数量的增加的主要原因,与其说是出生率的增加,不如说是医疗条件的改善导致的死亡率的降低