2012考研必备：考研英语语法精要(38)

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2.介词 + which的用法
    如果从句中主宾成分齐全，考生便可考虑关系代词是否在从句中做状语，而状语通常用介词短语充当，于是可以得知，关系代词前面应有介词，再分析所给的选项，根据与名词的搭配作出正确选择。如：
    Children are best served when schools contribute to shaping the solid foundation on which their future will be built.
    However, the batteries from which they(electric vehicles) draw energy usually contain harmful chemicals, which become pollutants when the batteries are disposed of.
    We are not conscious of the extent to which work provides the psychological satisfaction that can make the difference between a full and an empty life.
   
    3.非限定性定语从句前面有逗号标志，按汉语习惯通常翻译成两个句子
   
    切记：与汉语不同的是，英语中两个句子之间一般说来不能用逗号断开，而要用适当的连词或关系代词使它们形成从属或并列关系。据此可判断出逗号后面一句应由起连接作用的词开头。注意：有时关系代词前面还有其他附加成分。如：
    Biologists believe that rainforests are the home of perhaps half the world’s biotic species, about five-sixth of which have not yet been described and named.
    There are two spare rooms in the building, neither of which has been provided with modern facilities.