所有從句的簡化都是為了求精簡，省略主語是為了避免與之前的重復，省略be動詞是其本身無意義。副詞從句的簡化有五種不同的變化，我們分別講解。
一、簡化為Ving補語
如果副詞從句是進行時，省略主語與be動詞之后就是Ving形式，如果沒有be動詞和助動詞，就得先改成進行式再省略be動詞得到Ving形式：
① 連接詞是否保留
副詞從句的連接詞有一定的詞義功能，如while與before不同，雖然簡化了，但有時候也不能省略，只有當句子的意思足夠清楚的條件下才能夠將連接詞省略掉。
While lying on the couch, the boy fell asleep.
這一句中的while就可以省略，一般來說while（when）表示當……時，because、as、since表示因為，省略以后句子的意思依然完整，就可以省略。
② 沒有be動詞與助動詞
Because we have nothing to do here, we might as well go home.
普通動詞have，沒有be動詞可以省略，也沒有助動詞可以改寫就只有先變成be+Ving形式，這里不是進行時態，而是詞類的變化。
Having nothing to do here, we might as well go home.
注意：一般來說表示原因的連接詞because、since等都需要省略，如果加上會十分累贅。
③ 應該保留的連接詞
如果連接詞省略以后句子意思不清楚，就不能省略
Although we have nothing to do here, we can't leave early.
簡化成：
Although having nothing to do here, we can't leave early.
在這個句子中although表示一種轉折，不能省略。
同理：
He raised his hand, as if he was trying to hit her.
簡化成：
He raised his hand, as if trying to hit her.
as if 在這里表示好像，如果省略以后，讀者可能默認為因為要打她，句子的意思就會改變。
④ being的運用
be動詞一般在簡化時都需要省略，但有時候也不能省略的過頭了。
As I am a student, I can't afford to get married.
省略掉As I am以后，a student會被誤認為是主語或者同位語，不適宜全部省略。可改寫成：
As a student, I can't afford to get married.
Being a student, I can't afford to get married.
⑤ 連接詞before、after、since作介系詞
Before he was in school, he used to be a naughty child.
如果省略掉before he was就變成了：
In school， he used to be a naughty child.
沒有了連接詞before，就沒有從前在學校的意思了，但是如果單純的加上before in school，在語法上就有錯誤。before只能接名詞類。為了將in school改成名詞類，加入being即可：
Before being in school, he used to be a naughty child.
⑥ 時態問題
After he wrote the letter, he put it to mail.
簡化成：
After writing the letter, he put it to mail.
需要保留連接詞after，如果省略掉，就需要進行時態上的改變以保持句子原有的意思：
Having written the letter, he put it to mail.
⑦ 主語不同時
When the child was already sleeping soundly in bed, her mother came to kiss her goodnight.
從句的主語the child和主句的主語her mother是不同的，如果省略就變成了：
Already sleeping soundly in bed, her mother came to kiss her goodnight.
句子的意思表達不清楚，這時候就需要改變主語從句的結構，使得它與從句的主語一致：
Already sleeping soundly in bed, the child did not know it when her mother came to kiss her goodnight.
我們還可以保留兩個不同的主語，改寫成：
The child already sleeping soundly in bed, her mother came to kiss her goodnight.
注意事項：a、連接詞要省略，這里省略when；b、后面必須配合分詞補語（現在分詞、過去分詞）sleeping soundly，才能顯示省略了be動詞。
二、簡化為Ven補語
副詞從句如果原來是被動時態（be+Ven），簡化之后沒有了be動詞，就變成了Ven。
① 是否保留連接詞
Although he was shot in the knee, he killed three more enemy soldiers.
簡化以后不能省略掉連接詞although，因為although表達有“相反”的意思應該予以保留：
Although shot in the knee, he killed three more enemy soldires.
② before、after、since的特殊連接詞
Before it was redecorated, the house was in bad shape.
簡化為：
Before redecorated, the house was in bad shape.
副詞從句省略以后before不能省略，不然表達的意思就是裝修完成以后，和句子以前的意思不同。但是保留以后又會出現一個問題，就是before當介詞使用，后面要跟名詞類，我們加入being只是作為詞類的變化：
Before being redecorated, the house was in bad shape.
③ 如何處理having been
Because they had been warned, they proceeded carefully.
如果保留had been就改寫成：
Having been warned, they proceeded carefully.
如果省略掉hand been，就改寫成：
Warned, they proceeded carefully.
having been如果后面跟的是過去分詞，即使省略掉having been以后句子的意思仍然不變，也沒有語法上的錯誤。就可以省略掉。
④ 主語不同時
如果副詞從句與主句的主語不同，就得把主語保留下來
When the coffin had been interred, the minister said a few comforting words.
副詞從句的 主語是the coffin，主句的主語是the minister，并不相同。簡化時要同時保留：
The coffin interred, the minister said a few comforting words.
⑤ 助動詞改寫成to V形式
I'll only be too glad if I can help.
簡化成：I'll only be too glad to help.
⑥ 動詞只有be動詞時
只有當副詞從句的主語與主句的主語相同的時候才能將be動詞省略。
1> 介系詞短語
When you are under attack, you must take cover immediately.
簡化為:
When under attack, you must take over immediately.
2> 形容詞
While it is small in size, the company is very competitive.
副詞從句的補語是形容詞small，簡化的方式相同
While small in size, the company is very competitive.
3> 名詞
Although he was a doctor by training, Asimov became a writer.
簡化方式相同：
Although a doctor by training , Asimov became a writer.
總結：副詞從句的連接詞通常有意義，需要保留，所有后面的簡化沒有太大的變化。只是一些特殊的連接詞需要注意。
⑦ 改寫成介系詞短語
副詞從句改寫成介系詞短語，是大幅度的簡化。許多連接詞都要找到接近的介詞進行改寫，只剩下一個名詞空間來裝下整個從句的內容。
when——on\upon；because——with；although——despite\in spite of；if——in case of；等
1> if改成in case of：
If there should be a fire, the sprinkler will be started.
In case of a fire, the sprinkler will be started.
2> although改寫成despite
Although he opposed it, the plan was carried out.
Despite his opposition, the plan was carried out.
