请教一道语法题 T-3-Q31

brenda47

T-3-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 computer their longitude form the positions of the stars.

1. not, like more recently, motivated by complicated philosophical questions about the nature of matter and the universe, but the practical matters of navigation
   
   
2. being motivated by the practical matters of navigation, instead of complicated philosophical questions about the nature of matter and the universe, as it has been recently
   
   
3. motivated not by complicated philosophical questions about the nature of matter and the universe, like they were more recently, but by the practical matters of navigation
   
   
4. motivated by the practical matters of navigation, not complicated philosophical questions about the nature of matter and the universe, which was the case more recently
   
   
5. 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
   
   答案选E。用排除法能够选出来E，可是对于E 句中成分 as has been the case more recently 的作用不太了解。还望NN们赐教……谢啦
   

brenda47

自己顶，大家活跃一些哈

cocoloop

这是关系代词as引导的定语从句，有代替前面整个句子所说情况的意味。例如：china is a developing country,as is known to all.其实作用基本相当一个先行词，不同点在于as有“正如”正像“的含义，这也许是它能代替整个句子的原因。