代詞在閱讀過程中是難點(diǎn)之一。在英語中，為了語言的精練，避免重復(fù)，除了采用“省略”手段外，還廣泛地用代詞來代替上下文中已經(jīng)出現(xiàn)過的詞或提到的內(nèi)容。在閱讀過程中必須根據(jù)上下文的邏輯關(guān)系正確判斷代詞所代替的具體內(nèi)容，如分析不當(dāng)，往往會(huì)產(chǎn)生“張冠李戴”的錯(cuò)誤。必須指出的是，在各種代詞中it的用法最為復(fù)雜，it用作形式主語或形式賓語時(shí)，只有語法意義而沒有詞匯意義，可以說是“虛”的。但用作代詞時(shí)，代替某一詞或某一具體內(nèi)容，可以說是“實(shí)”的。it在句中表現(xiàn)得“真真假假，虛虛實(shí)實(shí)”，這給閱讀理解造成了很大困難，必須認(rèn)真分析和辨別。
為了語言精練，避免重復(fù)的目的，除了采用省略和代詞外，還采用另一種手段——近義詞(帶定冠詞the的近義詞)來替代上文中已出現(xiàn)過的詞，這種近義詞可稱為“替換詞”。
英語中常見的代詞有：one(ones)，that，they，those，the former，the latter等。“的用法較為復(fù)雜，特別加以歸納。
it的用法
(1)it作無人稱代詞：it作無人稱代詞表示自然現(xiàn)象、氣候、時(shí)間、距離等。it是形式主語沒有詞匯意義。如：
1)It is very cold today.(氣候)
2)It is three o’clock.(時(shí)間)
3)It is along way from here.(距離)
(2)it作人稱代詞：it作人稱代詞時(shí)，用來代替上下文中提到的事或物，有時(shí)可代替整個(gè)句子的內(nèi)容。
(3)his(was)+形容詞十不定式(to do)，it為形式主語，不定式短語為真正主語。
(過去分詞)
(4)his+{形容詞}+that(what，how，whether...)，it為形式主語，that引導(dǎo)的為主語從句。
(名詞)
(5)It+不及物謂語動(dòng)詞+that引導(dǎo)的主語從句。這些動(dòng)詞有：seem，appear，turn out，follow，happen等。
(6)It may well be that引導(dǎo)的主語從句。
(7)it作形式賓語：
1)某些及物動(dòng)詞+it+形容詞十不定式;
2)某些及物動(dòng)詞+it+形容詞+that...
在上述兩種句型中，it是形式賓語，真正的賓語是不定式短語，或that引導(dǎo)的賓語從句。
(8)it用于強(qiáng)調(diào)句型：
It is(was)十被強(qiáng)調(diào)的成分+that(which，who)
強(qiáng)調(diào)句型是簡單句，可以用來強(qiáng)調(diào)句中主語、賓語和狀語，但不能強(qiáng)調(diào)定語和謂語。在這種句型中把his...that去掉，句子仍成立。
代詞在句中分析與翻譯的實(shí)例
1.All the various transitions from one form of motion into another are governed by one ofthe fundamental laws of nature，that of the eternity of matter and its motion.
運(yùn)動(dòng)可以由一種形式變?yōu)榱硪环N形式，所有運(yùn)動(dòng)形式的變換都取決于一個(gè)基本的自然規(guī)律，即物質(zhì)及其運(yùn)動(dòng)永恒性的規(guī)律。(that代替one，one代替law。)
2.The author enumerate some of the factors which make it difficult for the sociologist to conduct experiments in the same way as his colleagues in the physical sciences.
作者列舉了某些使社會(huì)科學(xué)家難以進(jìn)行實(shí)驗(yàn)的因素，而在同樣的情況下，他的自然科學(xué)的同事們卻可以進(jìn)行實(shí)驗(yàn)。(it為形式賓語代替真正賓語to conduct...。)
3.The metallurgist has recently found a metal skin for missiles and supersonic planes，one that will retain its strength at the high temperature caused by air friction.
冶金學(xué)家最近發(fā)明了一種用于導(dǎo)彈和超音速飛機(jī)的金屬外殼，這種外殼在大氣摩擦引起的高溫下仍然能保持其強(qiáng)度。(one作同位語，代替skin。)
4.If one can scale down all dimensions to，let us say，one tenth，the average lengths of the current-paths will be reduced to one tenth.And the speed of operation will be scaled up 10 times.
如果人們能把所有尺寸縮小，比如說，減小到原來的1/10，那么電流路徑的平均長度也將減小到1/10，操作速度因而就會(huì)按比例提高10倍。(one泛指人。)
5.Underground water reserves are much larger than those on the surface，but as they are unseen we tend to understimate them.
地下水的儲量要比地面水大得多，但是由于看不到，所以往往低估了地下水的儲量。(those代替reserves。as引導(dǎo)原因狀語從句。them代替reserves。)
6.Here we find that the term work has been given by science a somewhat more limited meaning than that to which we have been accustomed.
這里我們發(fā)現(xiàn)，科學(xué)賦予“功”這個(gè)詞的含義比我們所習(xí)慣的“工作”這個(gè)詞的含義多少要狹窄一些。(第一個(gè)that是連詞，引導(dǎo)賓語從句。第二個(gè)that是代詞，代替work。)
7.We know that air can be compressed， and it is reasonable to suppose that the air at the surface of the earth is compressed by the weight of all the air on top of it.
我們知道空氣是可以壓縮的，因而我們有理由假設(shè)：地球表面的空氣受到該空氣層上部所有空氣重量的壓縮。(第一個(gè)it是形式主語，代替不定式短語to suppose...。句末的it是人稱代詞，代替“地球表面上的空氣”。)
8.It follows from the principle of relativity that Newton’s second law of motion，although fundamental in classical mechanics，only has an approximate and by no means complete validity.
由相對論原理可知，牛頓運(yùn)動(dòng)第二定律盡管是古典力學(xué)中的基本原理，但只是近似的，而決不是完全正確的。(It follows from...that....，“由……可以得出……”。It是形式主語，代替that引出的主語從句。)
9.It was supposed that bodies fall to the ground with a speed which is proportional to their weight。This means that if bodies of 100 pounds and 1 pound are pushed over a cliff，the former falls 100 times as fast as the latter.
曾經(jīng)有人設(shè)想，物體落地的速度與其重量成正比，這就意味著，如果把重100磅的物體和重l磅的物體從懸崖上推下去，前者下落速度是后者的100倍。(the former指bodies of 100 pounds，the latter指bodies of 1 pound。)
10 .Even though the same computer might have performed the same operation millions of times in succession， it must still be told exactly how to do that operation every time it repeats it.
即使同一臺計(jì)算機(jī)很可能已經(jīng)連續(xù)完成同樣的運(yùn)算達(dá)數(shù)百萬次之多，但每當(dāng)它重復(fù)這一運(yùn)算時(shí)都得準(zhǔn)確地告訴它如何去完成這一運(yùn)算。(句中有三個(gè)it,第一和第二個(gè)it都代替計(jì)算機(jī)，第三個(gè)it代替operation。might have performed是虛擬語氣，表示對過去發(fā)生事情的猜測。every time是連詞，引導(dǎo)時(shí)間狀語從句。that在句中不是連詞，是指示代詞，作operation的定語。)
