难句类型：复杂修饰、插入语
解释：主架构简单，可是主语和表语从句都不让人省心。句子的主干其实就是：A long-held view has been that..。但是主语A long-held view之后却是修饰它的一个三层的定语：of the history of the english colonies that became the United States。系动词has been之后所接的表语从句其实不止一个，其实原句是用了and来连接两个并列的表语从句，has been that…and has been that…。后面的has been照例被省略。
意群训练：A long-held view of the history of English colonies that became the United States has been that England’s policy toward these colonies before 1763 was dictated by commercial interests and that a change to a more imperial policy , dominated by expansionist militarist objectives , generated the tensions that ultimately led to the American Revolution .
68. It is not known how rare this resemblance is，or whether it is most often seen ininclusions of silicates such as garnet，whose crystallography is generally somewhat similar to that of diamond;but when present，the resemblance is regarded as compelling evidence that the diamonds and inclusions are truly cogenetic. (4)
现在尚不知这种类似稀少到何种地步，也不知道是否它最常见于象石榴石一类的硅酸盐内含物中，而这类物质的晶体结构普遍地在某种程度上类似于金刚石的晶体结构。但一旦存在，这种类似就被视作极有说服力的证据，证明金刚石与内含物确是同源的。
难句类型：复杂修饰、插入语
解释：本句的句子既长，专有名词又多，从句层出不穷，故而难懂。在本句中出现的专有名词中，除了silicates硅酸盐这个单词常常出现于理科文章中，需要记忆之外，其他单词阅读现场简单处理一番既可：inclusions可以猜出是被包含的物质;garnet作 感谢您阅读《历年GRE阅读材料难句精选100句(七) 》一文，出国留学网(liuxue86.com)编辑部希望本文能帮助到您。