第1个回答 2020-06-26
1.one, it, that常常用来代替或避免重复某个名词。
例如：
①I'm looking for a flat. I'd really like one with a garden.
②-Where did you find your watch? - I find it in our classroom.
③The population of China is larger than that of any other country.
2.one可指人或物，只替代单数可数名词，复数用ones. one是泛指，但有限定修饰语，如the, this, that…修饰就变成了特指。
如：One must do one's duty.
3.that只指物，不指人，可替代可数名词或不可数名词，具有“特指”性质。指的是同类事物中的另一样东西，即同类异物。如：The library of our school is bigger than that of yours.(that代替的是另一个图书馆。)
4．One 和that 在代替可数名词时，如果没有前置定语只有后置定语时， the one 和that可互换。但该名词如有前置定语，则只能用the one,而不能用that。
例如： ①I will take the seat next to the one(=that)by the window.我就坐窗口的那个座位旁边。
5．That的复数形式those代替可数名词的复数。可指人或物，一般后面跟修饰语。如： ①Today's cellphones are smaller than those(=the ones)used in the past.
6.the one(ones)或 that ,those 指代某一名词做定语从句的先行词时，其关系代词which在that之后，which不能省略，而在the one、ones 之后,which可省略。如：Their problem today is somewhat similar to that which they faced many years ago.
7.代替不可数名词时，应该用that。如：The equipment is different from that.
8.it代替上文所提到的名词时，是指同类事物中的同一样东西，即同类事物。如： I have lost my pen. I'm looking for it. 9.it和that可代替前面整个句子的意思，而one却不能；that可引导一个限定性定语从句，代替某个先行词（单复数名词均可），it和one则不能；it可代替不定式、动名词或从句，用作形式主语或形式宾语，也可用于强调句型中，而one和that则不能。