如果想在文憑試英文作文考到好成績，其中句子運用一定要變化。而我很喜歡教學生用倒裝句，因為倒裝句不太難學，最重要是在很多題目都可以大派用場。本文主要是理論篇，講清楚使用倒裝句的情況、倒裝的結構。倒裝句無論哪個情況，目的都是強調。
第一個使用倒裝句的情況是強調負面副詞詞組(adverbials)，例如：Under no circumstances should... (讀音:/ˈsɜː.kəm.stɑːns/ 或 /ˈsɝː.kəm.stæns/)/ In no way should … have …./ At no time.../ Not until .../ Little…./ Seldom.../ Rarely…/ Never...
例句:
Under no circumstances should the Hong Kong government ban the Korean visitors.
In no way could he buy a house without the subsidy from his parent.
Little does we know when the coronavirus will stop its spreading.
第二個情況是用only詞組開頭的句子，例如：only when/ ony after/ only if...。
例句:
Only when many people in Korea got the coronavirus did the Korean government started to panic.
Only if the Hong Kong government listens to the feedback of its citizens will the city have hope.
Only after the spread of the coronavirus has stopped will students be able to go to school.
以上三種結構十分好用，尤其是在寫說明的時候。因為說明文通常都要求給予建議，only when / only if/ only after的句子一定用得上。
除了only if/only when/only after外，not only...but also也十分常見。例如：
Not only has a worked in a Chinese restaurant in Prince Edward caught the Covid-19 virus, but a worker in the North Point KFC store was also infected.
第三個情況也是副詞開頭的句子，但不是負面副詞，而是與時間有關係的副詞，例如：hardly..when.../ scarcely...when/ no sooner...than等。
例句：
Hardly had I finished making the first teaching video when I needed to make another teaching video.
Scarcely had I marked the first homework when I had to start to mark the second homework.
No sooner had I read the first page of the book to my son than I started to read the second page.
留意以上三句的時態。在Hardly, Scarcely, No sooner子句中，要用過去完成式(past perfect tense)，在主句，則用過去式。
第四個情況是假設句。有趣的是，假設句三類都可以有倒裝句。以下是三種假裝句類型：
類型一：Should you have any questions in regards to the teaching video, please let me know.
類型二：Were the Hong Kong government to close the border to mainland China, the number of confirmed cases would drop.
類型三：Had the Hong Kong government closed the border to China, the number of confirmed cases in Hong Kong would have dropped.
最後第五種倒裝句情況是地點副詞開頭的句子，但這一種與以上四種都有些不同，因為以上四種倒裝在副詞後主語前都有助動詞(auxiliary)，但這種倒裝卻沒有，副詞後直接接動詞，是名副其實的倒裝，例：
Into the hospital came three patients.
Here is your money.
There goes the children.
留意第五種倒裝的主詞不能是代詞，如果是代詞，主語與動詞就不能倒裝，以上三句就變成：
Into the hospital they came.
Here it is.
There they go.
參考:
https://www.youtube.com/watch?v=i9CGTrpYnE8
