一、独立主格结构的定义与构成

独立主格结构是一种由名词或代词加上分词或分词短语构成的独立结构。它用于修饰整个句子，与其后的分词或分词短语之间存在逻辑上的主谓关系。这种结构在句中的位置相对灵活，可以通过逗号与主句分隔。例如：

1) Night enshrouding the earth, nobody could make out what the dark mass was from a distance.

2) He lay at full length upon his stomach, his head resting upon his left forearm.

3) The coward was backing, his face being deathly pale, toward another room.

二、独立主格结构的特殊形式

除了基本构成形式，独立主格结构还包括以下特殊形式：

1. 名词＋介词短语

- The mayor of Hiroshima strode at a leisure pace toward the puzzled journalist, a bunch of flowers in his hands.

- Every afternoon a very old woman hobbled past the ramshackle house, a vast load of firewood on her back.

2. 名词＋形容词(短语)

- The Trojans asleep, the Greek soldiers crept out of the hollow wooden horse.

- The wretched boy, who has recently been dragged from the forest to scrub floors in the barracks, is now sweeping away the snow, his hands numb with cold.

3. 名词＋副词

- This little excitement over, nothing was to be done but to return to a steadfast gaze at my mute companion.

- This intermezzo over, he found himself surrounded by several stunning, porcelain-faced Japanese women in kimonos.

三、独立主格结构的用法

独立主格结构在句中通常作状语，表达时间、条件、原因、伴随状况等。例如：

1. 作时间状语

- My shoes removed, I entered a low-ceilinged room, treading cautiously on the soft tatami matting.

- The governor pondering the matter, more strikers gathered across his path.

2. 作条件状语

- Weather permitting, they will go on an outing to the beach tomorrow.

- Such being the case, you have no grounds for dismissing him.

3. 作原因状语

- The storm drawing near, the navvy decided to call it a day.

- The Cossack being intent on his stalking, his foot touched the protruding bough that was the trigger.

4. 作伴随状语

- I took my ticket, and marched proudly up the platform, with my cheeses, the people falling back respectfully on either side.

- He would appear in the doorway, gray fedora pulled low over his face, his eyes sweeping the room for any sign of trouble.

四、独立主格结构的考试形式与策略

独立主格结构常在考试中以语法结构填空形式出现。解题策略包括结构分析法，即分析句子结构，判断缺少的成分，并注意主句与其他部分之间的连接。例如：

1) All flights ______, we decided to take a greyhound.

A. were canceled

B. had been canceled

C. having canceled

D. having been canceled

2) The production ______ steadily, the factory needs an ever-increasing supply of raw material.

A. has gone up

B. is going up

C. having gone up

D. being gone up

在解题时，应先进行初步判断，分析选项是否能构成状语从句或非限制性定语从句，或是否能构成非谓语动词短语或独立主格结构。根据句子意思和逻辑关系，选择正确答案。独立主格结构也常见于其他题型，对提高学生的综合应试能力有很大帮助。