让我们看个例子：Immediately, the police officer got out of the car and asked for my driver’s license. 

immediately放在句首，可以让句子更多样，看起来富于变化。

再看一个例子：Farmlands, However, were less possible to be polluted because of fewer factories in the past. 

那这句又把however又放在了主语的后边，谓语动词的前边，组成了一个插入语也可以，像这种句首的副词是一种变化方式。

看这个例子，In the arena, fans stood with their hands over their hearts and sang the National Anthem with the purpose of showing respect to their country.

大家注意看，这是一个单句，但是这句话写的也比较长，你看一下，开头是用了一个In the arena，然后在句子的末尾加了一个介词短语with purpose of doing something。

前边加了一个介词短语，后边加了一个介词短语，那整个这句话变得就比较长了，也变得比较多样了。所以说介词短语，也可以让你的句子变得多样，且长度增加。

比如说To win，或者是写成in order to win，candidates need to convey a clear message that is not contaminated by the opposition.。

前边加了一个in order to或者是to，也可以让句子变得多样，且长度增加。

比如说，Tapping the power of being seen, the Oscar nominees appeared onlate-night television, morning news programs, and in glossy magazines。

现在分词tapping就可以起到让句子开头有变化的这种作用，但是注意，tapping出现ing的时候证明这个词的主语跟后面主句的主语一致，这种情况下才可以使用ing的形式来开头。

同样呢，我们还可以使用过去分词做开头，但这种情况下要求后一句的主语要和前边的这个分词形成被动关系，比如说，Seen from the space, the Earth is a blue planet。其实就是 the earth is seen from the space, the Earth is a blue planet。

所以说这种情况下注意主动和被动关系就行了。

比如说：My embarrassment stemmed not from the money lost but from the notoriety gained.，所以这个地方在说的时候你要想清楚，你看这句话not from...，but from...，这样可以让你的句子变得更加的丰富。

接下来，She wanted her audience to remember the protest song and to understand its origin。to remember...，and to understand...，这两个不定式同时也构成了一个平行的结构。

下一句，The team members vowed that they would support each other, that they would play their best, and that they would win the tournament.

注意，这三个平行结构是怎么构成的呢?三个宾语从句，that...，that...，and that...，所以说这一下这个句子就能拉长。

再看下边一个例子，Whether her goals include publicizing student and faculty research or increasing research funding, she always works to improve research facilities.

whether后边加的是publicizing...or increasing...，所以说用doing的方式也可以构成平行结构。

比如说看例子：By contrast, people living in the city are suffering from various diseases caused by the environmental contamination, for pollutants from factories and automobiles are continually being discharged into the air and rivers.

这句话里边people living in the city其实就是people who live in the city，主动语态放在后边就可以用一个doing的形式来简化这个定语从句，后边那个various diseases caused by...，其实就是diseases which are caused by...

所以说这种过去分词也可以做后置定语，只要和前边的是个被动的关系就可以了。因此，分词结构也能够使句子变得更加丰富更加多样。