英语句子语法问题请各位帮下忙,宾语从句,状语从句,定语从句的语法,when and while 的区别和语法,还有if引

英语句子语法问题
请各位帮下忙,宾语从句,状语从句,定语从句的语法,when and while 的区别和语法,还有if引导从句（包括条件状语,宾语从句,和虚拟语句）的时态语法.

一.宾语从句就是在复合句中,用句子做宾语.常用的连词有that ,if ,whether ,what ,which ,who ,whom ,when ,where,how ,why等.
充当宾语从句的句子应该是本着主谓陈述语序的原则.
Can you tell me what he said just now?句中的what he said just now就是宾语从句,连词是
what ,he said主谓陈述语序,而不用一般疑问句句式did he say(x).
直接引语变间接引语就用宾语从句.
注意；1.主句谓语是现在时,将来时,宾语从句要用所需的时态.2.主句谓语是过去时,宾语从句的时态一定是过去某种时态,但客观真理仍用现在时.
She said the earth isn't round.
二.定语从句就是用句子充当定语,用句子修饰某一名词或代词.所修饰的词叫先行词,定语从句放在先行词的后面.关系代词有that,which,who ,whom ,whose ,关系副词when ,where,why.关系代词和关系副词放在先行词和定语从句中间,既起联系作用,同时又作定语从句的一个成分.
1.that指物指人都可.2which只指物.3who指人.4.when指时间5.where指地点,在定语从句中作地点状语.His father works in a factory that /which makes TV sets.他父亲在一家电视机厂工作.
句子中factory 是先行词,that/which makes TVsets是定语从句
The girls that /who are singing in the hall are our classmates.那些在礼堂里唱歌的女孩们是我们的同学.句中girls是先行词,that /who 是关系代词,that /who are singing in the hall是定语从句.
三.when 和while 都是”当……时候”讲.
1when引导时间状语从句+一般过去式,主句用过去进行时.
2.while引导时间状语从句+过去进行时,主句用一般过去式.
The children were leaving school when they saw a truck.当学生们看见一辆卡车时,他们正在准备离开学校.
While Jim was making a cake ,the bell rang.当吉姆在做蛋糕的时候,门铃响了.
四.状语从句：用句子充当状语.
时间状语从句：引导词有when,while ,till ,untill ,since,after,before,as soon as 等.
原因状语从句：引导词有because.
比较状语从句：引导词than
条件状语从句：if
让步状语从句：though/although
目的状语从句：so that
结果状语从句：so…that,…that…,such…that…
状语从句都本着：主将从现,就是主句用将来时时态,从句用一般现在时.
If it doesn't rain,we are going to the park tomorrow.if 引导的条件状语从句用一般现在时表示将来时.
虚拟语气从句也是if 引导.但是if +一般过去式,主句用过去将来时（would +动词原形）
If I was a bird ,I would be happy.