独立主格结构的句法功能

独立主格结构在句中一般作状语，表示时间、条件、原因、伴随状况等，还可以作定语。
1. 作时间状语
My shoes removed, I entered a low-ceilinged room, treading cautiously on the soft tatami matting.
我脱掉鞋子后，走进一间屋顶很低的房间，小心翼翼地踩在柔软的塌塌米垫子上。
The governor pondering the matter, more strikers gathered across his path.
总督思考问题时，更多的罢工工人聚集在他要通过的路上。
2. 作条件状语
Weather permitting, they will go on an outing to the beach tomorrow.
如果天气允许的话，他们将在明天组织一次海滨郊游。
Such being the case, you have no grounds for dismissing him.
如果情况如此的话，你没有理由解聘他。
3. 作原因状语
The boy leading the way, we had no trouble finding the strange cave.
由那个男孩带路，我们很容易就找到了那奇怪的洞。
There being no further business to discuss, we all went home.
没有别的事可讨论，我们都回家了。
4. 作伴随状语或补充说明
I took my ticket, and marched proudly up the platform, with my cheeses, the people falling back respectfully on either side.
我拿着车票还有我的奶酪，雄赳赳气昂昂地跨步走向月台。人们似乎很尊敬我，纷纷向两边退去。
Ten students entered for the competition, the youngest a boy of 12.
十个学生报名参加了这次竞赛，年纪最小的是个12岁的男孩。

独立主格与状语从句的转换

当状语从句的主语与主句的主语不是指同一个对象时，可用独立主格结构取代状语从句，但不再保留连词。
1. Class being over (Class over), the students soon left the classroom.
下课后，学生很快离开了课室。
=After class was over, the students soon left the classroom.
2. There being no further business, I declare the meeting closed.
工作都谈完了，我宣布会议结束。
=Since there is no further business, I declare the meeting closed.
3. It being Christmas, the government offices were closed.
现在是圣诞节，政府机关关门了。
=Because it was Christmas, the government offices were closed.

独立主格结构的特殊用法

1. 有些分词短语可以独立存在,在句子中没有逻辑上的主语，实际上已经变成了习惯用法。这些短语有：Generally speaking 总的说来；Frankly speaking 坦率地说；Judging from 从……判断；Supposing 假设等等。例句：
Generally speaking, the rule is very easy to understand.
总的说来，这条规则很容易懂。
Judging from what he said, he must be an honest man.
由他所说的来判断，他一定是一个诚实的人。
2. 有些固定短语是带 to 的不定式，表明说话人的立场或态度，在句中作独立成分。这些短语有：to be honest老实说；to be sure 确实；to tell you the truth 说实话；to cut a long story short 长话短说；to be frank 坦率地说；to make matters/things worse 更糟糕的是。例句：
To tell you the truth, I made a mistake in the word spelling.
说实话，我犯了一个拼写错误。