英語句型看似復(fù)雜多變，其實源于兩大鉆石句型，即①主語+謂語+賓語(S+V+O)和②主語+系動詞+表語(S+V+P)(注：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后有無賓語或補足語，具體為：主語+謂語、主語+謂語+賓語、主語+謂語+間接賓語+直接賓語、主語+謂語+賓語+賓語補足語，為了簡明扼要的說明問題，故將其總結(jié)為一種句型“主語+謂語+賓語”)。每一成分皆可復(fù)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復(fù)雜的長難句的。
一、句子擴展：修飾成分加長
(一)鉆石句型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.
注：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復(fù)雜化，從而增加理解難度。考研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.
注：謂語動詞like通過添加副詞短語、介詞短語、現(xiàn)在分詞短語、過去分詞短語、狀語從句等進行擴展，從而使句子變得復(fù)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(guān)系。
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.
注：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，從而使簡單句變得復(fù)雜化。考研翻譯中要注意這些修飾成分，如分詞結(jié)構(gòu)要找出邏輯主語等，定語從句要找出先行詞，等等。
(二)鉆石句型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.
注：此句的擴展同上(也是通過添加修飾成分變復(fù)雜)，不再贅述。
二、句子擴展：成分替換
句子的復(fù)雜不僅體現(xiàn)在修飾成分繁多上，還體現(xiàn)在句子成分本身的復(fù)雜化上，下面就通過句子成分由簡單到復(fù)雜的替換來演示句子是如何變難的。
(一)鉆石句型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.
注：由此可見，充當(dāng)主語的除了簡單的名詞(短語)、代詞、數(shù)詞，還可以是形式比較復(fù)雜的動詞不定式(短語)、動名詞(短語)、主語從句�？佳蟹g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.
注：由此可見，充當(dāng)賓語的除了簡單的名詞(短語)、代詞、數(shù)詞，還有形式比較復(fù)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，有助于打開思路，理清句子成分。
(二)鉆石句型②主系表句型
主語擴展：鉆石句型①中的主語擴展(成分替換)已經(jīng)很明確了，此處不再重復(fù)。
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.
注：由此可見，充當(dāng)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(dāng)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，并結(jié)合以上句子的擴展，體驗一下英文句子的各個成分及結(jié)構(gòu)。
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：