托福閱讀怎么抓住難句的主干

　　2.同位語

　　3.并列結(jié)構(gòu)

　　4.that引導(dǎo)的各種從句

　　5.插入結(jié)構(gòu)

　　6.獨(dú)立主格

　　7.倒裝句

　　8.強(qiáng)調(diào)句

　　9.虛擬語氣

　　對(duì)于不同類型的難句，把握主干的方法也不一樣。以倒裝句為例，主要有下列情況：

　　1.方位副詞放在句首　采集者退散

　　Herein lay the beginning of what ultimately turned from ignorance to denial of the value of nutritional therapies in medicine。

　　2.介詞放在句首

　　Among the species of seabirds that use the windswept cliffs of the Atlantic coast of Canada in the summer to mate, lay eggs, and rear their young are common murres, Atlantic puffins, black-legged kittiwakes, and northern gannets。

　　3. 形容詞放在句首

　　Implicit in it is an aesthetic principle as well: that the medium has certain qualities of beauty and expressiveness with which sculptors must bring own aesthetic sensibilities into harmony。

　　4.過去分詞放在句首

　　Accustomed though we are to speaking of the films made before 1927 as “silent”， the film has never been, in the full sense of the word, silent。

　　5.現(xiàn)在分詞放在句首

　　Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans。

　　句子倒裝的目的主要有兩個(gè)：

　　一是被提前的部分被強(qiáng)調(diào)，如上述的第四句：Accustomed though we are to speaking of the films made before 1927 as “silent”，其中的accustomed按照正常語序應(yīng)該放在are之后：Though we are accustomed to speaking of the films made before 1927 as “silent”。之所以將accustomed提前，是為了強(qiáng)調(diào)它。二是為了句子的平衡，否則將導(dǎo)致頭重腳輕的效果，如上述的第一句、第三句和第五句。以第五句為例，按照正常語序應(yīng)該是：Fossils clearly intermediate, or transitional, between land mammals and cetaceans were missing until recently。但是這種句子結(jié)構(gòu)比較糟糕，因?yàn)橹髡Z及其修飾語過長(zhǎng)(從句首直到cetaceans)，而謂語部分were missing until recently較短，容易造成頭重腳輕的效果。第五句將missing提前，避免了這一現(xiàn)象。