一、省略主語和動詞be

當狀語從句的主語與主句主語一致，且從句謂語包括有動詞be時，有時可省略從句中的主語和動詞be。如：

Phone me if (it is) necessary. 必要時給我打電話。

Start when (you are) ready. 準備好了就開始。

He danced about as if (he was) in search of something. 他向四周望望，仿佛在找什么似的。

Though (he was) intelligent, he was very poorly educated. 雖然他很聰明，受的教育卻很差。

注：有時省略的可能是 there is, it is 等。如：

There is few if (there is) any. 如果有也很少。

Fill in the application as (it is) instructed. 按照要求填好表格。

As (it is) scheduled they met on January 20. 他們按照計劃在1月20日碰頭。

二、結果狀語從句省略that

so that, so…that, such…that 引導結果狀語從句時，有時可省略that。如：

I am so busy (that) I have no time to write a letter. 我是那樣忙，寫信的時間都沒有。

He was so drunk (that) he could barely stand. 他喝醉了，勉強能站立。

The girls are so close (that) they're like sisters. 女孩們親如姐妹。

There was such a lot of rain (that) we couldn't go out. 雨那么大，我們沒法出去。

She spoke with such sincerity (that) he felt greatly touched. 她說得那樣誠懇，他深受感動。

三、比較狀語從句的省略

as, than等引出的比較大狀語從句通常省略謂語。如：

I know you better than he (does). 我比他更了解你。

He is as quick in answering as his sister (is). 他回答得和他妹妹一樣快。

He answers as quickly as his sister (does). 他回答得和他妹妹一樣快。

He is not so / as quick in answering as his sister (is). 他回答得不如他妹妹那樣快。

His sister is quicker than he (is). 他妹妹比他敏捷。

He moves more slowly than his sister (does). 他行動起來比他妹妹慢。