高中英语定语从句 as which that 有什么区别

定语从句学习绝妙窍门
一概念：1.定语从句：句子不定式反串形容词做定语.       2.先行词  ：先于定语从句出现被定语从句修饰的那个词.       3.关系词  ：引出定语从句并代替先行词在从句中充当一定成分的引导词.二引导词选用规则：1.分清人物.引导人用who/whom/that,引导物用which/that2.判断先行词范围是否明确,决定用限定还是描绘.that/why不能引导描绘性定语从句.先行词范围模糊（1.普通名词多样性2.专有名词自身比）用限定性从句.先行词范围明确（1.专有名词独特性2.普通名词唯一性）用描绘性从句.       3.判断先行词在从句中充当的成分.          a.若先行词在从句中充当主宾补同,人用who/whom/that,物用which/that,名词性引导词          b.若先行词在从句中充当定语,无论人物一律用whose,形容词性引导词          c.若先行词在从句中充当状语,时间用when,地点用where,原因用why,副词性引导词       4.习惯用法        . I必须使用who .1.当先行词是the one, anyone, those且在从句中做主语时                        2.当从句为描绘性定语从句,代替人在从句中做主语时                        3.当句型为there be或here be代替人在从句中做主语时                        4.当从句与主句被短语分隔开代替人在从句中做主语时         II必须用which. 1.当先行词是those, something代替物在从句中做主语或宾语时                        2.在描绘性定语从句中,代替物在从句中做主语或宾语时                        3.在描绘性定语从句中,代替主句在从句中做主语,当从句谓语为非be动词时                        4.当引导词代替物在从句中直接做介词宾语时         III.必须用whom1.当从句为描绘性定语从句,代替人在从句中作宾语时2.当引导词在从句中直接做介词宾语时         IV必须用that  1.当everything, anything, nothing, all, none充当先行词时.                        2.当先行词由every, any, all, some, no,little, few, much等修饰时,that常被省略                        3.当先行词前有序数词或最高级修饰时                        4.当先行词前有the very, the only, the just修饰时                        5.当先行词本身是who, which时                        6.当先行词是人物混有时                        7.当先行词前有the same修饰,两物为同一物时                        8.当先行词在从句中代替人做主补时         V必须用as    1.在描绘性定语从句中,当从句在主句之前时                       2.当先行词前有the same修饰,两物为类似物时                        3.当先行词前有such/so修饰或直接充当时         VI必须用than  1.当先行词前有比较级修饰时         VII必须用but  1.当先行词前有no/few/little修饰时,双重否定表示肯定时         VIII必须用what1.当先行词失去时         IX必须用where 1.当先行词是place以外的地点名词且前有介词时         X用副词that或in which  当先行词是the way