此类放在“数词 + 量词”后面的of,一般直接视为等同于's,而不能倒过来理解.
即在中文理解上,正常的A of B = B's A,但是此类结构的A of B = A's B.
如：my son's name = the name of my son
但是：ten years of hard work = ten years' hard work
two pieces of paper = two pieces' paper（只是汉字理解如此即可,不能真这么用英语表达）
所以：so many years of sunshine = so many years' sunshine,意思就是“这么多年的阳光”.