If the Greek mathematicians had not applied themselves to the investigation of conic section, zealously and without the least suspicion that it might someday be useful, it would not have been possible centuries later to navigate far from shore. 

参考译文：如果希腊的数学家们当时没有满怀热情的集中于椎体截面的科学研究，并且没有丝毫怀疑地认为将来有一天它会有用处的，那么就不可能会有数世纪之后的远离海岸的海上航行了。

1. 本句中的红色部分zealously and without the least suspicion that it might someday be useful中的and前后能算是平行并列结构吗？另外这部分该怎么翻译呢？

zealous and without the least suspicion that it might someday be useful，这一长串内容都是从句谓语动词had not applied“修饰成分”

其结构为："副词+介词短语"充当了从句谓语2种不同的状语,其中介词短语后面含有一个that引导的同位语从句。

(1)zealously（副词作方式状语）

(2)with the least suspicion that it might someday be useful（介词短语作伴随状语，伴随当时希腊科学家当时一种心态/观点/看法）

(3)that同位语从句具体说明the least suspicion的具体内容）

2. 整个这句话怎么翻译理解呢？

谢谢!谢谢!谢谢不吝指教了!

同意曹老师解答

以上句子结构为：对过去发生的事情的虚拟条件句

(1)从句用过去完成时态::If 主语 had (not) done sth

(2)主句用将来完成时态:主语+would(not) have done sth

（即：如果从句主语在过去不做某事，从句主语现在也就不会做某事）

句子语法结构如下

虚拟条件状语从句:If the Greek mathematicians had not applied themselves to the investigation of conic section

修饰虚拟条件状语从句谓语的状语成分:zealously and without the least suspicion that it might someday be useful,

虚拟条件主句:it would not have been possible centuries later to navigate far from shore. 

重点单词及短语解析如下

(1)apply oneself to sth使某人自己全神贯注于；使（注意力等）集中于

Faulks has applied himself to this task with considerable energy.

福克斯为这项任务倾注了大量精力。

(2)apply one's mind to sth使某人自己全神贯注于某事

In spare moments he applied his mind to how rockets could be used to make money. 在业余时间他潜心研究如何能用火箭来赚钱。

(3)Greek mathematician希腊数学们

(4)the investigation of   某事的调查/学术研究

(5)conic section   圆锥截面

(6)zealously adv. 热心地；热情地；积极地；狂热地

(7)without    prep.缺乏；没有;无，不用

(8)the least suspcicion  丝毫的怀疑；一丁点儿的怀疑

(9)with the least suspicion没有（丝毫怀疑/一丁点儿怀疑）

(10)someday  将来有一天;

(11)centuries later 数世纪以后/几个世纪之后

(12)to navigate far from shore 远离海岸的海上航行

(13)far from 远离；远非，不但不

(14)shore  n.海岸;河岸;湖滨

(15)navigate  vt.,vi航行，驾驶