天山3-31 as 的问题？

Q31
In the sixteenth century, the push for greater precision in measuring time was (not, like more recently, motivated by complicated philosophical questions about the nature of matter and the universe, but the practical matters of navigation):sailors simply needed more highly accurate timepieces in order to compute their longitude from the positions of the stars.
(E) motivated not by complicated philosophical questions about the nature of matter and the universe, as has been the case more recently, but by the practical matters of navigation

as 做关系代词引导一状语从句表示与主句的相似性;like则跟一名词结构表相似性,且比较的是主语.

as has been
                the case more recently = as more recently the push for greater precision in measuring time has been motivated not by complicated philosophical questions about the nature of matter and the universe...

意思是:就象 最近 对时间的量度要求更精确的现象的出现 不是由复杂的关于物质和宇宙的哲学问题引起的 一样,在16世纪, 对时间的量度要求更精确的现象的出现 也不是由复杂的关于物质和宇宙的哲学问题引起的,而是由航海的实际问题引起的.

用 has been the case 概括了与主句相同的部分,类似的省略在比较句中也很多,OG和大全都有,一下找不出来,只记得大概是: 主 谓 宾(其中有比较级)than it was ten years ago. 而主句的主语和谓语并不是对应的it was.

黄字疑为释疑者误打。