讲解一下英语的几种从句类型及其用法

讲解一下英语的几种从句类型及其用法
每种句子应注意什么,主句用什么时态,从句用什么时态. 帮忙讲解一下~

定语从句概要：（这是有关定语从句的精要介绍,涵盖了有关定语从句的各个方面,供参考：） 引导定语从句的关联词包括关系代词和关系副词.关系代词有that,which,whose,who,whom,as；关系副词有when,where,why.关系代词和关系副词在定语从句中都充当一定的句法成份.关系代词在从句中充当动词的宾语时一般可以省略.关系代词的选用比较复杂,受下列条件的制约：(1) 要看先行词是指人还是指物,(2) 要看关系代词在从句中句法功能,(3) 要看定语从句是限定性的还是非限定性的.在定语从句中充当的成分 ↓ 用于限定性或非限定性从句 只用于限定性从句 指人 指物 指人或指物 主语 who which that 宾语 whom which that 谓语 whose whose (of which) That 只能用在限定性定语从句中,而who,whom,which,which 既可用于限定性定语从句中,也可用于非限定性定语从句.I know that he is a man who means what he says.I know that he is a man that means what he says.【我知道他是一个守信用的人.】 The gentleman whom she met addressed her with courtesy.The gentleman that she met addressed her with courtesy.【她遇到的那位先生很有礼貌地向她打了招呼.】 The gentleman she met addressed her with courtesy.（在从句中充当动词宾语的关系代词,可以省略.） The watch which was lost has been found.The watch that was lost has been found.【丢了的表找到了.】 Here is the material which you need.(注：现代美语中不允许这样用) Here is the material that you need.Here is the material you need.【你要的材料在这儿了.】 You are the only one whose advice he might listen to.他也就是听你的话吧.关系副词的选用相对来说比较简单,如果先行词是表示时间的名词,如time,day 等,则用when,如先行词为表示地点的名词,如place,house,area 等等,则选用where.如果先行词为reason 则选用why I will never forget the mountain village where I spent my childhood.I will never forget the mountain village in which I spent my childhood.我永远也不会忘记我度过童年的那个小山村.I don’t know the reason why he did that.I don’t know the reason for which he did that.【我不知道他为什么这么做.】 当先行词是all,something,nothing 等不定代词时,或者先行词的前面有first,last,only,few,much,some,any,no 等词修饰时,或者先行词的前面有最高级修饰时,一般只用that 而不用which 来引导定语从句：I have explained everything that I can to you.I have explained everything I can to you.【我已经尽一切可能把事情向你解释得一清二楚.】 具体详情请上百度百科查询.从句—请点击此连接就可查询各种从句的具体解释 http://baike.baidu.com/view/138129.htm