副词提至句首引起倒装，可分以下几种情况：

　　1、only + 副词（when，before，if，after等）或only+介词状语（由in，under，by，on，after等引导）提前，必须部分倒装。

　　如：Only then did he realize how stupid he had been.

    Only after entering the store did Arthur realize that there was dan ger.

　　Only in the library can she concentrate on her study.

　　2、often，such，so等副词提前，部分倒装。

　　如：So diligently did he work that he got hight scores on the final exam. =He worked so diligently that he got hight scores on the final exam.

　　Such was his wish that the world would stay away from war forever.

　　Often did we go on a holiday in hot summer. 注意，so的另一种倒装是表示“也…”。

　　California relies heavily on income from crops，and so does Florida. 加利福尼亚过多的依赖于来自农作物的收入，佛罗里达也是这样同理，体会一下neither，nor的倒装。

    He can't dance，neither/nor can I.= I can't，either.

　　他不会跳舞，我也不会。

　　3、in，out，down，up，away，off，here，there，over等副词提前，全部倒装。

　　如：Off got the staggering gentlemen.

　　Here are the photos I took at the seaside.

　　疑问句需部分倒装语序，由于经常用到不会成为考试的难点。

　　如：What part did he play in Hamlet？

　　Do you prefer tea or coffee？

　　by可视为被动语态的标志词，by之后的名词短语是句中动作的施动者；在题干中若见到by+名词的结构要优先考虑用被动式

　　如：The wall is painted by Tom.

　　The book was written by Mark Twain.

　　注意1：by之后如果接的是动名词，则表示方式、手段，不能视为被动式的标志，且此时谓语应用主动式，如：He passed the exam by cheating.

　　注意2：对于know来讲，一般用be known to而不用be know by强调句中it作形式主语可以替代任何被强调的部分基本模式：It + be + 强调对象+ who/ whom/that + 句子其余部分。

　　如：It was only you who cared for me. （强调主语）

　　It is his sister whom /that I have fallen in love with. （强调宾语）

　　It was under the tree that she found her missing purse. （强调地点状语）

　　It was last week that I attended an art exhibit for the first time. （强状语）

　　It was not until he broke my favorite vase that I flew into rages. （强调状语从句）

　　注意：强调的对象是人时，可用who，whom或that，其余情况一律用that；当强调对象在从句中做主语时用who/that，当强调对象在从句中做宾语时用whom/that。

　　虚拟语气

　　此章内容在TOEFL考点中处于相对次要地位，但在英文中是比较活跃的用法，必须对其有所了解，这样对读题非常有帮助虚拟语气是英文中一特殊的语言现象，主要用于表达与事实相反的陈述，常表达强烈愿望、遗憾、感慨、后悔、责备、规劝等语义，可大致分为三类。

　　对现在事实的虚拟基本形式：If + were /did等过去式…，…would /could /should /might + do

　　例如：If I were a bird，I would fly to the moon.

　　（事实上，I' not a bird，so I will not fly to the moon.）

　　If she knew who you are，she would go out of joy.