每日一句：2017考研英语第三句

Aluminum remained unknown until the nineteenth century, because nowhere in nature is it found free, owing to its always being combined with other elements,
most commonly with oxygen, for which it has a strong affinity.
词汇突破：1.Aluminum 铝
          2.Free 元素的游离状态
          3.Affinity 归属感
      He has a close affinity with the landscape he knew when he was growing up...
            他对这片从小就了解的土地有着一种归属感。
            Affinity for 一种元素对于另一种元素的亲和力
主干识别： Aluminum remained unknown
           铝一直没有被人发现；
切分成分： 1. because nowhere in nature is it found free, owing to its always being combined with other elements, most commonly with oxygen, for which it has a strong affinity.
2. until the nineteenth century.
独立成句：1.because nowhere in nature is it found
                      = Because it is found nowhere in nature.
由于在自然界找不到游离状态的铝;
2.owing to its always being combined with other elements, most commonly with oxygen
由于它总是跟其他元素结合在一起;最普遍的是跟氧结合
3.for which it has a strong affinity.
Which= oxygen
It = aluminum
= aluminum has a strong affinity for the oxygen
铝跟氧有很强的亲和力。
调整语序：中文习惯先翻原因，再翻结果
参考译文： 铝总是跟其他元素结合在一起，最普遍的是跟氧结合，因为铝跟氧有很强的亲和力，进而在自然界找不到游离状态的铝；所以，铝直到19世纪才被人发现。