But even more important, it was the farthest that scientists had been able to look into the past, for what they were seeing were the patterns and structures that existed 15 billion years ago.(1998,71)
这个句子中That existed 15 billion years ago.是一个定语从句，其先行词是the patterns and structures.这个定语从句比较简单，我们可以直接将其翻译他所修饰的先行词的前面。
译文：但更为重要的是，这是科学家们所能观察到的最遥远的过去的景象，因为他们看到的是150亿年前宇宙云的形状和结构。
二、单独成句
当一个限定性定语从句的结构较为复杂，意义较为繁杂的时候，如果把它翻译在其修饰的先行词的后面的话，会显得定语太过于臃肿和复杂，而无法让评卷老师看的清清楚楚，明明白白。所以这个时候我们要把定语从句单独翻译出来,放置于原来它所修饰的词的后面当定语。同时当定语从句是一个非限定性定语从句的时候，往往也要单独成句。
Tylor defined culture as “...that complex whole which includes belief, art, morals, law, custom, and any other capabilities and habits acquired by man as a member of society.” (2003,64)
在这个句子中，whole后面是一个很长的定语从句，无论从结构和意义上看都较为复杂，所以翻译时可以和先行词拆开。
译文：泰勒把文化定义为“一个复合体”，它包括人作为社会成员所获得的信仰、艺术、道德、法律、风俗以及其它能力和习惯。
The Greeks assumed that the structure of language had some connection with the process of thought, which took root in Europe long before people realized how diverse languages could be.(2004,61)
“which took root in Europe long before people realized how diverse languages could be.”是非限定性定语从句，修饰前面整个句子;在定语从句中long before引导时间状语从句修饰动词短语Take Root，在状语从句中又包含了一个由how引导的宾语从句，作realized的宾语。句中Take root in作“扎根“讲。因此这个非限定性定语从句是较为复杂的，所以我们采用单独成句的翻译方法。