托福閱讀：如何找準(zhǔn)句子主干

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托福要想拿到高分，閱讀是必須拿高分的。然而，很多學(xué)生詞匯背了很多，閱讀也做了很多，成績(jī)提升卻不明顯。長(zhǎng)難句分析一直是很多學(xué)生薄弱的地方，那么，我分享一些分析長(zhǎng)難句的方法。

分析長(zhǎng)難句的核心在于抓住主干，分析修飾成分。

Part One

第一， 什么是句子主干？

答案是，五大基本句型。

主語(yǔ)+謂語(yǔ)（不及物動(dòng)詞）           Legends abound.

主語(yǔ)+謂語(yǔ)+賓語(yǔ)                    I ate an apple.

主語(yǔ)+表語(yǔ)+系動(dòng)詞                  She is sleeping.

主語(yǔ)+謂語(yǔ)+直接賓語(yǔ)+間接賓語(yǔ)       My father bought me a car.

主語(yǔ)+謂語(yǔ)+賓語(yǔ)+賓語(yǔ)補(bǔ)語(yǔ)           I found this computer useful.

不管多么復(fù)雜的句子，句子的主干都跑不了這五種基本句型。但是仍有些需要注意的地方。

1、 找主語(yǔ)

大部分情況下，主語(yǔ)都是位于句首的第一個(gè)名詞、代詞、數(shù)詞、動(dòng)名詞或者動(dòng)詞不定式。這兒指出兩個(gè)容易犯錯(cuò)的地方。

1） 代詞也可以做主語(yǔ)

Another, advanced in the twentieth century, suggests that humans have a gift for fantasy, through which they seek to reshape reality into more satisfying forms than those encountered in daily life.

這是個(gè)代詞做主語(yǔ)的情況，且another 后省略了名詞，它就是句子的主語(yǔ)。

2） 句首出現(xiàn)介詞短語(yǔ)

倒裝 Among the main factors are Teotihuacán’s geographic location on a natural trade route to the south and east of the Valley of Mexico, the obsidian resources in the Teotihuacán Valley itself, and the valley’s potential for extensive irrigation.

這是介詞短語(yǔ)位于句首倒裝的情況，句子主干是Location，the obsidian resources and the valley’s potential are among the main factors.

基本結(jié)構(gòu)是 A is among B. 介詞短語(yǔ)做句子成分的情況，是在主系表結(jié)構(gòu)中做表語(yǔ)。

做修飾成分  In these shops differences of rank were blurred.

在這個(gè)句子中，出現(xiàn)了介詞in，句子又是正常語(yǔ)序，有些學(xué)生會(huì)誤把shops 當(dāng)做主語(yǔ)，其實(shí)介詞+名詞構(gòu)成介詞短語(yǔ)大部分都是起修飾作用，在這個(gè)句子中是限定發(fā)生的地方。

2、 找謂語(yǔ)動(dòng)詞

這個(gè)對(duì)很多學(xué)生來(lái)說(shuō)，都是個(gè)大難點(diǎn)。

1）、非謂語(yǔ)動(dòng)詞VS謂語(yǔ)動(dòng)詞

顧名思義，非謂語(yǔ)動(dòng)詞就是不可以做謂語(yǔ)的動(dòng)詞，有三大類：動(dòng)詞不定式（to do）、現(xiàn)在分詞(-ing)和過(guò)去分詞（-ed）。

現(xiàn)在分詞用法 

現(xiàn)在分詞（短語(yǔ)）后置，表主動(dòng)

eg. The man holding a magazine is my father.

現(xiàn)在分詞放在名詞前，表主動(dòng)、正在進(jìn)行的

eg. China is a developing country.

過(guò)去分詞用法

過(guò)去分詞（短語(yǔ)）后置，表被動(dòng)

The job finished by this group is a marvelous.

過(guò)去分詞前置，表完成的動(dòng)作，無(wú)被動(dòng)含義

a sank ship沉船   a fallen leave 落在地上的葉子  a falling leave正在飄落的葉子

如何區(qū)分過(guò)去分詞是做謂語(yǔ)動(dòng)詞還是做修飾成分？

a、 看時(shí)態(tài)，如果是一個(gè)過(guò)去分詞的動(dòng)詞一個(gè)現(xiàn)在時(shí)態(tài)的動(dòng)詞，則一般過(guò)去分詞修飾，因?yàn)楝F(xiàn)在時(shí)態(tài)的動(dòng)詞不可能做修飾成分

The environmental changes associated with this transition are not fully understood, but people living closest to the San Juan Mountains, to the northeast of Mesa Verde, were affected first.

b、 過(guò)去時(shí)態(tài)，一個(gè)be動(dòng)詞的過(guò)去式，一個(gè)其他動(dòng)詞的過(guò)去式，則動(dòng)詞是be動(dòng)詞的過(guò)去式

c、過(guò)去時(shí)態(tài)，都是實(shí)義動(dòng)詞的過(guò)去式，根據(jù)句子意思和搭配來(lái)判定

2）、主語(yǔ)和謂語(yǔ)被插入語(yǔ)隔開

This “atmospheric engine”, invented by Thomas Savery and vastly improved by his partner, Thomas Newcomen, embodied revolutionary principles, but it was so slow and wasteful that it could not be employed outside the coal mines for which it

had been designed.

主干：This “atmospheric engine” embodied revolutionary principles.

The central state, though often very rich and very populous, was intrinsically fragile.

3）、在從句修飾主語(yǔ)或者主語(yǔ)后的其他修飾成分太長(zhǎng)的情況下，誤把從句中的動(dòng)詞當(dāng)做謂語(yǔ)動(dòng)詞。

At one time, the animals present in these fossil beds were assigned to various modern animal group.

3、 找賓語(yǔ)

1）、賓語(yǔ)太長(zhǎng)后置，導(dǎo)致找不到賓語(yǔ)

But the myths that have grown up around the rites may continue as part of the group’s oral tradition and may even come to be acted out under conditions divorced from these rites.

2)、從句做賓語(yǔ)

The structure of the backbone shows, however, that Ambulocetus swam like modern whales by moving the rear portion of its body up and down, even though a fluke was missing.

3）、插入語(yǔ)把謂語(yǔ)和賓語(yǔ)隔開

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