什么时候用ONE作同位语?什么时候有用it

什么时候用ONE作同位语?什么时候有用it
例：The number 2008 is a special number,one I think,that will be remembered by the Chinese forever
这个句子为什么用one

英语替代词one,it 和that的用法
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.they B.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