定语从句(Attributive Clause)
在复合句中修饰名词或代词的从句称为定语从句，被定语从句所修饰的词称为先行词，定语从句必须置于先行词之后，定语从句是研究生及四、六级等各类考试的常考点，也是语法重点，本节将着重讲解：
1. 引导词关系代词：which， that， who(m)， whose， as
关系副词：when， where， why
例句： Johnson & Johnson， for example， has created BabyCenter， a standalone media property that promotes complementary and even competitive products. (选自2011年Text 3)
分析： 该句是复合句。其中，for example作插入语，a standalone media property与BabyCenter为同位语关系；that promotes complementary and even competitive products是一个定语从句，修饰BabyCenter。
译文： 例如，强生公司创建了宝宝中心网站，它是一家独立的媒体资产，用于推广互补的甚至是竞争性的产品。
例句： This trend began during the Second World War，when several governments came to the conclusion that the specific demands that a government wants to make of its scientific establishment cannot generally be foreseen in detail. (1996年第72题)
分析： 该句是复合句，主干部分为This trend began during the Second World War，when引导一非限制性定语从句修饰the Second World War；that a government wants to make of its scientific establishment是修饰the conclusion that...这一同位语从句中demands的定语从句， 而同位语从句的主干为the specific demands cannot generally be foreseen in detail， 其中make demand of sb. /sth.意为“向某人或某事提出要求”。
译文： 这种趋势始于第二次世界大战，当时一些国家的政府得出结论：政府向科研机构提出的具体要求通常是无法详尽预见的。
例句： One reason why it is hard to design and teach such courses is that they can cut across the insistence by top American universities that liberalarts educations and professional education should be kept separate， taught in different schools. (选自2011年Part B)
分析： 该句是复合句。其中，主句的主干部分是One reason is that they can cut across the insistence；why it is hard to design and teach such courses是一个定语从句，修饰reason；that liberalarts educations and professional education should...in different schools是insistence后的同位语从句。
译文： 这种课程很难设计和讲授的原因之一就是它们打破了美国顶尖大学一贯坚持的原则：人文教育与专业教育应该独立，并在不同的学院讲授。
2. 限制性定语从句和非限制性定语从句
定语从句根据其与先行词关系的密切程度分为限制性定语从句和非限制性定语从句，限制性定语从句是把主从句看作一个整体，因而关系紧密，不用逗号隔开，从句去掉后，主句不能单独成立；非限制性定语从句是把主从句分开考虑，因而关系松散，通常用逗号隔开，从句去掉后，主句也能单独成立，在引导词中除关系代词that和关系副词why外，其他均可引导非限制性定语从句。
例句： It applies equally to traditional historians who view history as only the external and internal criticism of sources， and to social science historians who equate their activity with specific techniques. (1999年第75题)
分析： 该句是复合句，介词短语to traditional historians与to social science historians并列，每个介词短语都由各自的定语从句来修饰。
译文： 这种谬误同样存在于历史传统派和历史社会科学派。前者认为历史就是史学界内部和外部人士对各种史料来源的评论，后者认为历史的研究是具体方法的研究。
例句： By contrast， they saw in the preceding hundred years from 1650 to 1750， when England was still a completely agricultural country，a period of great abundance and prosperity. (选自1998年Cloze Test)
分析： 该句是复合句，主干部分为they saw in the preceding hundred years from 1650 to 1750 a period of great abundance and prosperity，非限制性定语从句when England was still a completely agricultural country修饰hundred years。
译文： 相比之下，他们认为从1650年到1750年的100年间，虽然英国还是一个完全的农业国，但这一时期是富裕和繁荣的时期。
例句： Toyota Motor， for example， alleviated some of the damage from its recall crisis earlier this year with a relatively quick and wellorchestrated socialmedia response campaign， which included efforts to engage with consumers directly on sites such as Twitter and the socialnews site Digg. (选自2011年Text 3)
分析： 该句是复合句。其中，主句的主干部分是Toyota Motor alleviated some of the damage from its recall crisis earlier this year；介词短语with a relatively quick and wellorchestrated socialmedia response campaign作状语，表示方式，修饰动词alleviated；which included efforts to engage with consumers directly on sites...是一个非限制性定语从句，修饰campaign。
译文： 例如，丰田汽车公司通过发动相对迅速、精心安排的社交媒体回应活动，包括在微博Twitter和社会新闻网Digg等网站上与消费者直接互动，缓解了今年早期的召回危机所造成的部分损失。
