一、one的用法

　　one作替代词,相当于"a(an)+名词"。用来代替前面出现过的"同类"事物,one代替单数可数名词,ones代替复数可数名词,one不能代替前面的不可数名词。如:

　　1. I hope there are enough glasses for each guest to have ____.

　　A. it B. those C. them D. one

　　2. -Why don't we take a little break?

　　-Didn't we just have____?

　　A. it B. that C. one D.this

　　3. Mr Zhang gave textbooks to all the pupils except ____ who had already taken them.

　　A. the ones B. ones

　　C. some D. the others

　　二、it的用法

　　it用作替代词,代替前面提到过的事物"本身",而one代替前面提到过的"同类"事物。如:

　　1. The Parkers bought a new house but ____ will need a lot of work before they can move in.

　　A. theyB. it C. one D. which

　　2. Tom's mother kept telling him that he should work harder, but ____ didn't help.

　　A. he B. which C. she D. it

　　it可作形式主语

　　当动词不定式、动名词或从句作主语时,通常把它们放在谓语之后,而用it作句子的形式主语。如:

　　____ is a fact that English is being accepted as an international language.

　　A. There B. This C. That D. It

　　it可作形式宾语

　　当复合宾语中的宾语是不定式、动名词或宾语从句时,往往把宾语放在它的补足语后面,而用it作形式宾语,放在宾语补足语之前。如:

　　I hate ____ when people talk with their mouths full.

　　A. it B. that C. these D. them

　　it可用于强调结构

　　要强调句子的某一成分(通常是主语、宾语或状语),常用的结构是"It is/was+被强调部分+that/who+句子的其余部分"。如果被强调的部分是人,可用who, whom代替that。如:

　　1. Was it during the Second World War ____ he died?

　　A. that B. while C. in which D. then

　　2.It is the ability to do the job ____ matters, not where you come from or what you are.

　　A. one B. that C. what D. it

　　it可用于it doesn't matter句型中。如:

　　Does____ ____matter if he can't finish the job on time?

　　A. this B.that C. he D. it

　　三、that的用法

　　that作替代词,相当于"the+名词",that与it一样,指前面所提到过的事物"本身",that后可有of短语作后置修饰语,但it不可以。that既可代替前文出现过的单数可数名词,又可代替不可数名词。如:

　　-He was nearly drowned once.

　　-When was____?

　　-____was in 1998 when he was in middle school.

　　A. that; It B. this; This

　　C. this; It D. that; That

　　(文/谢仕芳；英语辅导报高三版2003-2004学年第27期；版权归英语辅导报社所有，独家网络合作伙伴新浪教育，未经许可，不得以任何形式进行转载。)