So的倒装句是英语中一种常用的语法结构，在语言表达中可以起到强调、突出的作用。So引导的常用倒装句有以下三种用法：
1. "So + 形容词/副词 + 主语" 倒装，表示强调程度。例如："So beautiful was the scenery that I couldn't help taking a photo."（如此美丽的风景，我无法抵挡拍照的冲动）。
2. "So + 动词/情态动词 + 主语" 倒装，表示强调动作的结果或程度。例如："She worked so hard that she passed the exam."（她学习非常努力，以至于通过了考试。）。
3. "So + 主语 + be/助动词 + 主语/宾语" 倒装，表示强调主语或宾语。例如："So does he."（他也是这样的。）"So have I."（我也有这样的经历。）。
so的倒装句可以让语言表达更加突出，强调更加明显，使得听者更加容易接受信息。
So倒装句是英语中一种常见的语法结构，其主要用法有以下几种：
1. 表示因果关系。
正常语序是“因为……，所以……”，但是在so倒装句中，可以把so放在句首，使句子更加强调结果。例如：
- I was tired, so I went to bed. --> So tired was I that I went to bed.
- She passed the exam, so she was really happy. --> So happy was she that she passed the exam.
2. 表示疑问。
当我们想表示疑问时，可以在so后面加上主语，实现倒装。例如：
- He is leaving, so soon? --> So soon is he leaving?
- You are happy, so why are you crying? --> So why are you crying if you are happy?
3. 强调。
在正常语序中，我们使用强调词来强调句子的某个部分，但在so倒装句中，我们可以使用so来达到同样的效果。例如：
- She is a famous actress. --> So famous is she that she can't walk down the street without being recognized.
- He is an excellent chef. --> So excellent is he that people come from all over the world just to taste his food.
so倒装句是英语中一种特别的语法结构，可以用来表示因果关系、疑问和强调。掌握这种语法结构可以帮助我们更好地理解英语中的复杂句子，更加流利地表达自己的意思。
常用的so句首倒装句有两种情况：一是so+助动词/be动词+主语；二是so+形容词/副词+主语+动词。
第一种情况的例句：
- So happy was she that she couldn't stop singing.
- So tired was he that he fell asleep right away.
- So pleased were they with the result that they celebrated all night.
第二种情况的例句：
- So loudly did he speak that everyone could hear him.
- So beautifully does she sing that it touches people's hearts.
- So quickly did they finish the task that they had time to relax.
使用so句首倒装句可以使句子语序更加紧凑，强调程度更高，为英语写作和口语表达增添了更多的表现力。但需要注意的是，so句首倒装句的使用应该恰如其分，过多的使用会使文章显得不自然。