英語(yǔ)長(zhǎng)難句令很多考生都頭疼的一部分，但是其實(shí)英語(yǔ)長(zhǎng)難句本身并不難，只是因?yàn)槌鲱}者在簡(jiǎn)單句上擴(kuò)充，形成了一個(gè)生詞多、句子長(zhǎng)、結(jié)構(gòu)復(fù)雜的句子。要想分析長(zhǎng)難句本身，首先要找到句子主干，再看其他分支具體是做什么成分，這樣就要求考生們具有一定的語(yǔ)法知識(shí)，才能很好的分析出這些句子成分。因此，考研英語(yǔ)老師為大家講解考研中常見(jiàn)的英語(yǔ)語(yǔ)法。
獨(dú)立主格結(jié)構(gòu)由名詞或代詞加上其他成分(分詞、不定式、名詞、代詞、形容詞、副詞或介詞短語(yǔ))構(gòu)成。
獨(dú)立主格結(jié)構(gòu)沒(méi)有主語(yǔ)和謂語(yǔ)，所以在語(yǔ)法上不是句子。但多有名詞或代詞表示的邏輯主語(yǔ)，分詞或不定式表示的邏輯謂語(yǔ)，有時(shí)還有其他修飾成分。(判斷一個(gè)結(jié)構(gòu)是否是句子的標(biāo)準(zhǔn)就是看看這個(gè)結(jié)構(gòu)是否有謂語(yǔ)動(dòng)詞。)這種結(jié)構(gòu)通常在句子中起方式、時(shí)間、原因、條件等狀語(yǔ)或狀語(yǔ)從句的作用，主要用于書(shū)面語(yǔ)。使用動(dòng)詞非謂語(yǔ)形式的獨(dú)立主格結(jié)構(gòu)可以改為句子形式(從句):獨(dú)立主格結(jié)構(gòu)加上連詞，非謂語(yǔ)動(dòng)詞改為謂語(yǔ)動(dòng)詞形式，這樣就成為從句了。
例如:
Today being Sunday,the library isn't open.今天星期天，圖書(shū)館不開(kāi)放。
(原因)改為從句:
As(Since)today is Sunday,the library isn't open.
例如:
There being no buses，we had to take a taxi.沒(méi)有汽車(chē)了，我們只好坐出租車(chē)了。
Because there were no buses,we had to take a taxi.
The signal given，the bus started.信號(hào)發(fā)出后，公共汽車(chē)就啟動(dòng)了。
(時(shí)間)改為從句:
After the signal was given,the bus started.
The boy followed that man here，and climbed in，sword in hand.少年跟那個(gè)人到這里，并爬了進(jìn)來(lái)，手里拿著劍。
The boy followed that man here，and climbed in，and had a sword in his hand.
The mid-term examination is over,the end-of-term examination to come two months later.期中考試結(jié)束了，兩個(gè)月之后進(jìn)行期末考試.
The mid-term examination is over,and the end-of-term examination is to come two months later.
Weather permitting,we'11 visit the Great Wall.如果天氣允許的話，我們就去參觀長(zhǎng)城。
If weather permits,we'11 visit the Great Wall.
The boy followed that man here,and climbed in,sword in hand.少年跟那個(gè)人到這里，并爬了進(jìn)來(lái)，手里拿著劍。(伴隨狀語(yǔ))
上文例句中sword in hand是由“名詞+介詞短語(yǔ)”構(gòu)成，表示伴隨的情況。這種表示伴隨情的獨(dú)立主格結(jié)構(gòu)，有時(shí)可以用with引出，二者的意思是一樣的，with結(jié)構(gòu)更加口語(yǔ)話，更加常用。
She left the office with tears in her eyes.她眼里含著淚水，離開(kāi)了辦公室。
The teacher walked into the classroom,with a ruler under his arm and some books in his hand.老師胳膊底下挾著一把尺子，手里拿著幾本書(shū)，走進(jìn)了教室。
The teacher walked into the classroom.He was holding a ruler under his arm and some books in his hand.
Tian'anmen Square looks magnificent with all the lights on.華燈齊放，天安門(mén)廣場(chǎng)顯得美麗動(dòng)人。
With the boy leading the way,we found his house with no difficulty.由這孩子領(lǐng)路，我們毫不費(fèi)勁地找到他的家。
With him to give us a lead,our team is bound to turn out well.有他給我們帶頭，我們隊(duì)一定能搞好。
