Inversion in English
今天花了一点时间，学习了一下英文中的倒装句（Inversion），下面是 一些学习的记录。
倒装句的规则是：把一个句子的助动词（Auxiliary）和主语（Subject）位置互换。
句子结构如下：
auxiliary + subject + main verb
例句：
Scarcely have they been on time. # 他们很少准时
这里的主语（they）和助动词（have）的位置，相较于正常陈述句，就发生了互换。
倒装句用于强调一件事的独特性（unique），常常以否定开头。
下面我们分别来看倒装句的类型和用法。
1. Never, Rarely, Seldom
倒装句中的Never, Rarely和Seldom用来表现给定情况的独特性（unique）。
它们与动词的完成时（perfect）一起使用，有时句子中会包含一个比较对象。如：
1. Never have I been more insulted.
2. Rarely has someone as tall as you. # 包含比较对象
2. Hardly, Barely, No sooner, Scarcely
倒装句中的Hardly, Barely, No sooner, Scarcely用于描述一组连续的动作，
表达第一件事刚刚完成，第二件事就发生了。
1. Scarcely had I got out of bed when the doorbell rang.
2. Barely had I walked in the door when my dog came rushing to greet me.
3. 带Only的短语，如Only after, Only then
这一类型的倒装句，表示只有在...的情况下，才...。如：
1. Only then did I understand the problem.
2. Only after understanding the situation does the teacher make a comment.
3. Only when all the stars have gone out will I grasp the complexity of the universe.
值得注意的是，这类的倒装句，带Only的短语有时是直接和从句连接，
这时主句却需要倒装，如上述的例句2和例句3。
4. Little
这类的倒装句，表示...很少，或是很少...。如：
1. Little did he understand the situation.
2. Little did she play basketball.
5. So & Such
So的语法为：So + adjective + be + ... + that + ...，如：
1. So difficult is the test that students need three months to prepare.
Such的语法为：Such + be + noun + that + ...，如：
1. Such was the day that we will all remember forever.
6. 条件句（If ...）
条件句的倒装形式会让人听起来显得更加正式一些。规则是去掉If，把
助动词提前。如：
原句：If I had had enough money, I would have brought a new house.
1. Had I had enough money, I would have bought a new house.
原句：If he should decide to come, please telephone.
2. Should he decide to come, please telephone.
以上。