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.
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。