定从和同位语从句的区别
1、学生最容易混淆的是定语从句与同位语从句的区别。
例如：A 、The news that our team has won the match is true． (同位语从句)
B、The news that he told us surprised everybody here． (定语从句)
关键的区别在于连接或关系代词that ：有意义的是定语， 无意义的是同位。因为引导定语从句的that 在从句中作主语或 宾语，而引导同位语从句的that 只起到连接词的作用。
2、接着容易混淆的是引导定语从句的关系代词that 与 which：that 之前是不定(代词) 、序数(词) 、(形容词) 最高级：which 之前是介词短语与逗号(非限制性) 。
例如：A 、All that we have to do is to practise every day．
B、The first lesson that I learned will never be forgotten．
C、I have lost my pen，which I like very much.
D、The house in front of which there is a garden is my home． It 的用法
形式主语
然而有少数表语之后接动名词作真正的主语。这些表语是：无助(no help)、无用(no use)、没好处(no good)；工作(hard work费时(a waste of time)、又危险(a danger)。、
It 还可以作形式宾语。通常下列动词后面可接it 作形式宾语：2f2tcjm(find，feel,think,take,consider ，judge, make)。
倒装结构
学生容易混淆的是全部倒装与部分倒装。如何区分之，编个顺口溜：副(adv.)介(prep．) 提前全倒装，其它句式部分倒；否定提前倒助动，让步状语倒表语；复合句式倒主句，不
倒装的属特殊。下面举例说明：
A 、Here comes the bus．(副词提前，全倒装)
B 、Here he comes.(代词作主语，不倒装)
C 、In front of the house lies a garden.(介词短语提前，全倒装)
D 、Never shall I do this again.(否定词提前，部分倒装)
E 、Young as he is ,he knows a lot.(让步状语从句，表语倒装)
F 、Only when he told me did I realize what trouble he was in．(only 修饰状语，主句倒装)
G 、Only he can save the patient.(only修饰主语．不倒装)
H 、Not only will help be given to people,but also medical treatment will be provided.(否定词提前，部分倒装)
I 、Not only he but also we like sports.(连接两个主语，不倒装)
虚拟语气
虚拟语气也是一个难点。所谓虚拟语气是表示说话人的愿望、假设、猜测或建议，而不表示客观存在的事实。它通过句子的谓语动词的特殊形式来表示。现归纳如下：纯假设，用虚拟，动词时态退一级：条件句，分主从，主句谓语前加would (should,could，might) ；表愿望, 用虚拟，wish 后面接宾语(从句) ：现在过去与将来，动词时态退一级：提建议，用虚拟，宾语(从句) 动词用(should)do：俩建议，三要求，再加坚持与命令
(suggest,advise,demand,require,request,insist,order)：It is time和eoukd rather,后接丛句用虚拟：部分主语从句中， 谓语用虚拟结构 (It is necessry
/important/natural/natural/strange/strange that……should do)。 下面举例说明：
A 、If you came tomorrow,we would have the metting. (条件句虚拟)
B 、Without air,there would be no living things.(同上)
C 、We wish we had arrived there two hours earlier.(表示愿望虚拟）
D 、He demanded that we (should)start right away.(表示建议虚拟) E 、It is(high)time that we left (should leave)now．(特殊从句虚拟） F 、I would rather you gave me the book．(同上)
G 、It is necessary that we should clean the room everyday，(主语从句虚拟) H 、He speaks English so fluently as if he were English． (特殊从句虚拟)