英语中的从句到底是啥?怎么理解

英语中的从句到底是啥?怎么理解
什么宾语从句,谓语从句等等的,都不懂啊

1.主语从句 1）主语从句可直接位于主语的位置,如果从句较长,谓语又较短,可用it作形式主语,而将从句放在句末.常见的句型有：*it is a fact\a pity\a question\good news that...2)what引导的主语从句表示“...的东西时”,一般不用it作形式主语.what we lack is experience.3)what,who,when,why,whether等词含有各自的疑问意义,但它们引导的主语从句,都用陈述语序.how the plan is to be carried out should be discussed again.2.宾语从句 1）宾语从句可位于及物动词、介词和某些形容词后.连词that常可省略.介词后一般接疑问词引导的宾语从句.in that(因为),except that(除了),but that(只是）已构成固定搭配,其他介词后一般不接that引导的宾语从句.*i promised that i would change the situation.2)宾语从句后如有宾补,要用形式宾语it来代替,而把宾语从句移至宾补之后.he has made it clear that he would not change his mind.3)在think,believe,suppose,expect等动词后的宾语从句中,如果谓语是否定的,一般将否定词移至主句谓语上,宾语从句则变成肯定形式.he didn’t think that the money was well spent.3.表语从句 表语从句出现在结构为“主语+系动词+表语从句”的句子中.表语从句除可用that,what,when,why,whether,how等引导外,还可由because,as if(though)等引导.that常可省略.如主句主语为reason,只能用that引导表语从句,不可用because.4.同位语从句 同位语从句用于对前面出现的名词作进一步说明,一般用连词that引导,由于先行名词的意义不同,也可用whether,who,when,where,what,why,how等引导.常见的先行名词有fact,idea,belief,news,hope,conclusion,evidence,suggestion,order,problem,report,decision.有时由于谓语较短,将同位语从句位于谓语之后.she finally made the decision that she would join the fashion show.5.定语从句 定语从句所修饰的先行词可以是名词或代词,也可以是一个句子.定语从句通常位于先行词之后,由关系代词或关系副词引导.*限制性定语从句 限制性定语从句修饰先行词,对先行词起修饰作用,紧接先行词之后,无逗号,若省去,原句意思不完整.引导定语从句的关系代词有who,whom,whose,which,that等.who,whom,whose用于指人,whose有时也可指物,相当于of which；which用于指物；that既可指人也可指物,但只用于限制性定语从句中.关系代词除了引导定语从句,替代先行词外,还在从句中担任主语、宾语、定语等.the computers and cables which make up the internet are owned by people and organizations.1)当先行词是all,anything,everything,something,nothing等不定代词或先行词前有first,last,any,few,much,some,no,only以及形容词最高级修饰时,只能用关系代词that引导从句.that is all that i’ve heard from him.2)关系代词的省略 在从句中作宾语的关系代词常可省略.关系代词紧跟介词,作介词宾语时不可用that,只可用which或whom引导从句,并且不可省略,但当介词位于宾语从句句末时,作为介词宾语的关系代词仍可用that,也可省略.this is one of those things with which we have to put up.个人建议最好是去买本英语语法书耐心研究一下吧