考研英語長難句其實並不難，找到了破解的秘鑰就可以輕鬆過關。任何難題的解決都要從根源處著手，長難句的破解得先看句型，及其根源，只要掌握了兩大基本句型及其擴展的規律，要攻克長難句也就是順其自然了。下面我們一起來看看。
英語句型看似複雜多變，其實源於兩大鑽石句型，即
①主語+謂語+賓語(S+V+O)和
②主語+系動詞+表語(S+V+P)
本句型總共有4種形式，分別因謂語動詞的不同特點而決定謂語之後有無賓語或補足語，具體為：
1)主語+謂語
2)主語+謂語+賓語
3)主語+謂語+間接賓語+直接賓語
4)主語+謂語+賓語+賓語補足語
每一成分皆可複雜化，由此加大了句子的理解難度。下面就演示一下這兩大基本句型是如何擴展成複雜的長難句的。
一、句子擴展：修飾成分加長
(一)鑽石句型①主謂賓句型
The boy (主語) likes (謂語) English (賓語).
1.主語擴展：
The clever boy likes English.
The boy with a book in his hand likes English.
The boy who is full of imagination likes English.
The clever boy who is full of imagination with a book in his hand likes English.
註：主語中心詞為the boy, 可以通過加形容詞、介詞短語、定語從句及其組合等成分使主語複雜化，從而增加理解難度。考研(課程)翻譯中的主語考點多為修飾成分繁多的主語。
2.謂語擴展：
The boy likes English very much.
The boy likes English out of interest.
The boy likes English influenced by his parents.
The boy likes English, hoping that one day he can go abroad.
The boy liked English when he was five years old.
註：謂語動詞like通過添加副詞短語、介詞短語、現在分詞短語、過去分詞短語、狀語從句等進行擴展，從而使句子變得複雜，增加了理解難度。考研翻譯中注意找準動詞及其修飾成分,以弄清邏輯關係。
3.賓語擴展：
The boy likes American English.
The boy likes English, the international language.
The boy likes English which is the most widely spoken language in the world.
The boy likes English spoken by many people nowadays.
The boy likes English, a beautiful language, spoken by many people living in every corner of the world.
註：賓語English通過添加形容詞(短語)、同位語、定語從句、分詞短語及其組合進行擴展，從而使簡單句變得複雜化。考研翻譯中要注意這些修飾成分，如分詞結構要找出邏輯主語等，定語從句要找出先行詞，等等。
(二)鑽石句型②主系表句型
The girl (主語) is (系動詞) Mary (表語).
各部分擴展：
The girl in a pink hat with a book in her hand is probably Mary a kind-hearted girl of inexhaustible energy which often amazes her classmates.
註：此句的擴展同上(也是通過添加修飾成分變複雜)，不再贅述。
二、句子擴展：成分替換
句子的複雜不僅體現在修飾成分繁多上，還體現在句子成分本身的複雜化上，下面就通過句子成分由簡單到複雜的替換來演示句子是如何變難的。
(一)鑽石句型①主謂賓句型
主語擴展：
The event amazed the world.
What happened on that day amazed the world.
To hold the Winter Olympics in China amazes the world.
Holding the Winter Olympics in China amazed the world.
That China is to hold the Winter Olympics amazes the world.
註：由此可見，充當主語的除了簡單的名詞(短語)、代詞、數詞，還可以是形式比較複雜的動詞不定式(短語)、動名詞(短語)、主語從句。考研翻譯中明確這一點，才能打開思路，更好地劃分句子成分，從而做到真正理解句意，進而很好的用漢語表達出來。
賓語擴展：
He can hear me.
He can hear the strange sound.
He can hear anything happening in the building.
He can hear the sound from that building.
He can hear a girl crying in the building.
He can hear whatever happens in the building.
He decided to check what’s going on in the building.
He considered going to the building for a look.
註：由此可見，充當賓語的除了簡單的名詞(短語)、代詞、數詞，還有形式比較複雜的動詞不定式(短語)，動名詞(短語)，賓語從句。同樣的，考研翻譯中明確這一點也非常重要，有助於打開思路，理清句子成分。
(二)鑽石句型②主系表句型
主語擴展：鑽石句型①中的主語擴展(成分替換)已經很明確了，此處不再重複。
表語擴展：
They are beautiful.
They are in the zoo.
They are beautiful animals in the zoo.
They are interested in the new invention.
To see is to believe.
That is what we are talking about.
註：由此可見，充當表語的成分繁多，有形容詞(短語)，介詞短語，動詞不定式(短語)，分詞(短語)，名詞，表語從句。在考研翻譯，中若這些充當表語的成分變得更長一些，要注意識別。
三、示例
通過下面這個例子，並結合以上句子的擴展，體驗一下英文句子的各個成分及結構。
But science does provide us with the best available guide to the future, and it is critical that our nation and the world base important policies on the best judgments that science can provide concerning the future consequences of present actions.
解析：
並列句。第一個分句主幹：science does provide us。其中with the best available guide to the future為狀語修飾provide，the best available和to the future分別為guide的前置定語和後置定語，由此本句賓語被複雜化; 第二個分句主幹：it is critical that...,其中，it為形式主語，that從句為真正的主語，從句主語為名詞短語our nation and the world, base...on...為固定搭配，第二個that從句為judgments的定語從句，分詞結構concerning...為judgments的後置定語。
(責任編輯：田學江)