小编前言：阅读是四级英语中重要的得分点和难点，对长难句的分析则决定了对阅读的彻底理解，也是学习语法，积累高级词汇、句型不可或缺的来源。而四级英语真题阅读部分均选自Times、Telegraph等著名外文报纸及杂志，其行文和词汇原汁原味，值得考生细细品味和灵活借鉴。准备2014年6月英语四级的同学们，还等什么？赶快学起来吧！同时，欢迎各位考生针对例句的翻译及分析给出自己的理解哦！

1. There are many communities and populations which have lost precious records due to tragic events such as the fire in the Irish courts during Civil War in 1921 or American slaves for whom many records were never kept in the first place. (2002. 12. 阅读. Text 4)
【译文】有许多群体和民族曾因为某些悲剧性事件失去了他们宝贵的记录，例如1921年发生在美国内战期间爱尔兰法庭的那场大火，又例如美国奴隶，他们的记录从一开始就未能得到保存。
【析句】复合句。主句是there be结构，There are many communities and populations,紧随其后，which have lost precious records...为定语从句修饰many communities and populations。而定语从句中，due to介词短语作原因状语，在such as引出的第二个例子后又有定语从句for whom many records were never kept...。

2. Once the database has enough samples to represent the world genetic make-up, it will eventually help in solving many issues regarding genealogies that could not be done by relying only on traditional written records. (2002. 12. 阅读. Text 4)
【译文】一旦数据库获得足够多的样本代表世界基因组成，那最终会帮助解决许多与谱系相关的问题，而这些问题往往不能依赖传统的书面记录得到解决。
【析句】本例句是从句-主句+从句的结构。首先，句首是once引导的原因状语从句，中间是主句it will help in solving many issues regarding genealogies，最后是that引导的定语从句修饰genealogies。写英语作文时，可参照这种句型，根据句子之间的逻辑关系，写出更地道的英语句子。

3.  “For example, if two men sharing the same last name believe that they are related, but no written record proves this relationship, we can verify this possibility by collecting a sample of DNA from both and looking for common markers (in this case we can look primarily at the Y chromosome ),” explains Ugo A. Perego, a member of the BYU Molecular Genealogy research team. (2002.12.阅读.Text 4)
【译文】杨百翰大学分子谱系研究小组成员Ugo A·Perego解释道，“例如，如果两个姓相同的人认为他们有亲戚关系却没有书面记录能够证明，我们可以通过收集两人的DNA样本并寻找共同的遗传标记来证明这种可能性（这种情况下，我们主要看Y染色体的异同）。
【析句】本例句引用了某人所说的一段话，主句很容易判断，是Ugo Perego explains，这里将主句后置且倒装，为了突出说话的内容同时也是本句的重点。看一下引号内的部分，首先是if引导的条件状语从句，从句中主句two men sharing the same last name believe that...,sharing the same last name为现在分词作定语，believe后是that引导的宾语从句，but连接与从句主句是转折关系的并列句；we can verify this possibility by collecting...and looking for...是主句，by+动名词作方式状语。

本文句子翻译及解析为沪江英语原创，转载请注明出处。