首先，我们先来看一个句子：
Playground supervision will be more effective if members of staff are trained to recognise the difference between bullying and to fight playfully.
这个句子有什么问题吗？
来，我们缩小范围：
Playground supervision will be more effective if members of staff are trained to recognise the difference between bullying and to fight playfully.
没错，不协调呀！
既有between…and…的句式，把to fight playfully 换成 playful fighting是不是更好？
老师说
平行结构是一种修辞手法，它使得句子前后保持平衡和协调，从而增加语言的连贯性，它要求词与词，短语与短语，句子与句子一一对应。
词典中，对于“Parallelism”，即“（句子）排比，平行结构”是这么解释的—the use of matching sentence structure, phrases, or longer parts so as to balance ideas of equal importance（用匹配的句子结构、短语或更长的结构来平衡同等重要的思想和概念）。
举个栗子
我们来看几个雅思阅读中的句子感受下它的平衡和协调之美。
例1：Imaging fairy-tale turrets( 童话中的炮塔) and fire-breathing dragons (喷火龙), wicked witches (邪恶的女巫) and gallant heroes (英勇的英雄), she’s creating an enchanting world. --C14
例2：It’s regarded as something trivial (琐碎的), or even as something negative (负面的) that contrasts with “work”.
--C14
例3：Significantly, though, just fulfilling these needs does not result in satisfaction (并不会带来满足), but only in the reduction of dissatisfaction (而只会减少不满).--C14
嗯~会用平行结构，措辞就可以琅琅上口~
