一、it和that都替代"the+单数名词（可数或不可数）"，都是特指，但it指前面提到的"同一"事物，而that是指前面提到的"同类"事物。如：

　　1. The Parkers bought a new house but ________ will need a lot of work before they can move in. （全国卷）

　　A. they   B. it   C. one  D. which

　　「分析」答案选B.it替代"the + house"，指的就是前面提到的the Parkers所买的那座新房子。

　　2. Few pleasures can equal ________ of a cool drink on a hot day. （全国卷）

　　A. some   B. any   C. that     D. those

　　「分析」答案选C.that替代the pleasure，指与前面提到的同属"快乐的事".

　　二、one替代"a＋单数可数名词"，表示泛指。特指的the one相当于that；the one复数形式the ones，在口语中也常用those代替；当后面有of短语时，一般用that或those，当有前置修饰语时，只能用one（s），如the red one.one（s）， the one（s）， those， that都是替代"同类"事物，其中只有that可替代不可数名词。如：

　　1. We needed a new cupboard for the kitchen. So Peter made ________ from some wood we had. （广西卷）

　　A. it      B. one      C. himself      D. another

　　「分析」答案选B.one替代"a cupboard".

　　2. Meeting my uncle after all these years was an unforgettable moment，________I will always treasure. （全国卷）

　　A. that       B. one   C. it        D. what

　　「分析」答案选B.one替代"a moment"，作an unforgettable moment的同位语。后面接的是它的定语从句。又如Cook was a strict but good captain，one who took good care of the sailors on his ship.

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

　　-Didn't we just have ________ ？ （全国卷）

　　A. it     B. that     C. one           D. this

　　「分析」答案选C.one替代a break.

　　4. Mr Zhang gave the textbooks to all the pupils except ________ who had already taken them. （全国卷）

　　A. the ones   B. ones C. some   D. the others

　　「分析」答案选A.后面的定语从句是特指，the ones替代the pupils.此处也可用those.

　　再试试以下的高考题例：

　　1. （07四川） Little joy can equal ____ of a surprising ending when you read stories.

　　A that    B those    C any     D some

　　2. （07陕西） -There is still a copy of the book in the library. Will you go and borrow _____？

　　-No， I'd rather buy ____ in the bookstore.

　　A it， one    B one， one    C one， it     D it， it

　　3. （07辽宁） The information on the Internet gets around much more rapidly than ____ in the newspaper.

　　A it    B those    C one   D that

　　答案：

　　1、A.that替代joy，属于不可数性的名词，只能用that.

　　2、A.第一空it代替the book，是同一本书。第二空代替books的任何一本，等同于a book，所以用one.

　　3、D.that代替不可数名词information.