简单概述一下it ，one和that的用法跟区别

1. 要点提示 it可以用作人称代词，它还可以指时间、天气、距离、上下文等，另外，it还可以作先行词，作形式主语和形式宾语。 2. 用法指南 (1)作为人称代词，it可以用来指东西、动物、婴儿和未确定身份的人。 Where's my book? Have you seen it? 我的书在哪里？你看见了没有？ The dog is in the garden, isn't it? 狗在花园里，是吧？ The baby cried because it is hungry. 婴儿哭了，因为他/她饿了。 (Someone is ringing.)Who's it? It's me. (有人在按门铃。)谁呀？是我。 (2)it 可以指上下文内容 The Olympic Game will be held in Beijing in 2008. It makes the Chinese proud. 2008年将在北京举行奥运会。这使得中国人非常自豪。 (3)it表示时间、天气、距离等。 What time is it now? It's half past nine. 现在几点了？九点半 It is cold.天气冷。 It's about ten kilometers from the park to the museum. 公园到博物馆大约是十公里。 (4)it用作形式主语或形式宾语 It's very important for us to learn English well.(实际主语是to learn English well) 对我们来说，学好英语很重要。 I found it hard to fly a kite. (实际主语是to fly a kite) 我发现放风筝很难。 ''one''的 用法归纳起来有下列几种 一、作数词用。 1. 具有形容词性，有“一”之意。如： one half一半；one or two days一两天 I only have one thing to stay. 此时one比a语气强些。 2. 具有名词性，有“一；一个；一个人”等意。如： How many sisters do you have? I have one. One of the boys is not here. 此外，one用在名词后，“第一”的意思。如： No. one , Page One, Picture One 二、作形容词用。 1. 与表示时间的名词连用，构成副词性词组，作“某一”，“有一”等解时，其前不加介词。如： one morning(night)有个上午(晚上)，one Friday有一个星期五 注意，one day既可指过去“有一天”，也可指将来“有朝一日”。细读下面两句子： One day a young man came to see me. One day we'll go to the moon by spaceship. 注意区别下面两个句子，前一句用one，前面不加介词；后一句用a，前面加了介词。 One summer afternoon I met him in the street. One a summer a afternoon I met him in the street. 2. 有"the same''之意，即“同一的”“一致的”。如： in one voice异口同声地 ; one price一样价钱 It is all one to me. 这对我是一样的。 3.有“（作对比）一方的”意思。如： from one side to the other从一头到另一头 To say is one thing and to do is another 说是一回事，做又是另一回事。 三、作代词用 。 1. 作不定代词，有“任何人”，“谁都”的意思。如： One must love one's (his) country谁都必须爱国。 One for all and all for one.个人为集体，集体为个人。 2. 代表人称代词，“个人”，“某人”之意。如： run as fast as one can尽量跑得快马 do one's best 竭尽所能，尽力 3. 作“一个”，“一本”，“一件”等解，用来代替上文提到过的某个可数名词，以避免重复，其前不加任何限定词。如： My pen is broken. I must buy one. ''Have an apple, please." "No, thanks. I've just had one." 注意：one与it都可替代上文出现的某个名词，但用法不同。one用来指代上文出现的某类物中的一个，it指代上文中出现的那个物。细读下文，仔细比较： 1) A: Do you have a knife? B:Yes, I have one. A: Give it to me ,please. B: OK. Here it is. 2) A: Do you have any pencils? B: Yes, I have one.（此时复数形式用some）(Yes, I have some.) 3) A: Would you like the watch? B: Yes, I'd like it. 4. one与形容词连用时，其前常有a, the, this, that, next,last, my, her等限定词。如： a small one, the blue one, my new one, his big one, your old one（one前有形容词修饰时，才可以与形容词性物主代词或名词所有格连用。如：Jim's new one) 5. one可以与疑问代词(which)、相互代词及序数词连用。如： 1) Which one is yours? 2) This one is too heavy. Give me another one. 3) The second one is bigger. 6. one的复数形式为ones。但要注意：ones只有在其前修饰语时才能用。如： Which ones are theirs? The blue ones are theirs. I want big ones, I don't want small ones. 7. 作对比用时，one为“一个、一方”之意。如： 1) There are two(three) balls. one is yellow. The other is (The others are) black. 2) This is my sock. The other one is under the desk. 8. these ones与those ones很不普通。如最好不说：These ones are not good. I want those ones.要说：These are not good. I want those. “that”在英文中是一个使用频率很高的单词。它有四种词性，并且句法及语法功能纷繁复杂。如果不能熟练掌握其用法，很可能会形成英语学习的一种障碍，从而影响其学习兴趣和效率。现将that的用法总结归纳如下： 第一、that 用作形容词（后接复数名词时用those）。 它用来指已被提到的人或物；也可表对比，指两个中较远的那个。 What about that book you borrowed from me last month？ 请注意，that 有时候在句子中具有喜欢或轻蔑等感情色彩。 that little son of his 他那个小宝贝儿子 That George！乔治那家伙！（含有轻蔑语气） 第二、that 用作代词。 1. that 用作指示代词（复数形式是those），其指代意义同形容词用法，同时它还可以用作定语从句中的先行词；还可为了避免重复，代替前述名词。 That is what he told me. What is that (which) you have got in your hand? The price of rice is higher than that of flour. 2. that 用作关系代词，引导限制性定语从句。先行词可人可物，用法相当于who或which。（但是在下列情况下多用that：先行词既有人又有物时；先行词有形容词最高级、序数词、不定代词、very，only等修饰时；先行词是不定代词时） He talked about the teachers and schools that he had visited. I think it one of the most wonderful films that the film company has ever produced. She has little information that is useful for our research. Is there anything that I can do for you? 请注意，that 在定语从句中作宾语时通常可省略。 The books (that) I sent you will help you in your studies. 第三、that 用作连词，引导名词性从句,状语从句和强调句。 1. that名词性从句。 ①引导宾语从句。及物动词后的引导词that可省略。 I didn't expect (that) he could win the championship. The teacher pointed out that Tom was not working hard enough. ② 引导主语从句。通常采用it作形式主语的句型。 That the earth goes around the sun is known to everyone. （It is known to everyone that the earth goes around the sun.） ③引导表语从句。 The trouble is that we are short of money. ④引导同位语从句。 引导同位语从句的that和引导定语从句的that是不同的。前者只起语法作用，在从句中不作任何成分；而后者在定语从句中作主语、宾语或表语。举例说明： The news that he resigned from office surprised us. The idea that he holds is very common nowadays on campus. 2. that引导状语从句 ①引导目的状语从句。 Bring it nearer that I may see it better. ②引导结果状语从句。 What have I done that he should be so angry with me? ③引导原因状语从句。 I am afraid that I will fail in the driving test. ④引导让步状语从句。意为“虽然、尽管”。 Difficult that/as the task was, they managed to accomplish it on time. ⑤引导条件状语从句。意为“假使、假设”。 Supposing that you were in my position, what would you do? On condition that you were lost in the desert, you should ask for help as soon as possible. 3. 引导强调句。 It is Mrs. White that makes the decision in her family, not her meek little husband. It is an ill wind that blows nobody good. 第四、that用作副词。 1. that用作普通副词。 I was that/so angry I could have hit him. 2. that用作关系副词。引导定语从句，可以代替when，where， why或 in which，常可省略。 I will never forget the evening (that) / when we went to the theatre. The house (that)/where I used to live has been knocked down. 第五，与that 有关的常见重要短语。 1. in that，意为“既然、因为”。 Criticism and self-criticism is necessary in that it helps us correct our mistakes. 2. now that，意为“既然、由于”。 Now that they have taken matters into their hands, the pace of events has quickened. 3. see (to it) that，意为“注意、务必做到、保证”。 We will see to it that she gets home early. See to it that you are not late again. 4. seeing that，意为“鉴于、由于”。 Seeing that it is 8 o'clock, we'll wait no longer. Seeing that he was busy with his work, I didn't disturb him. 以上是that主要用法的概述，希望能对你有所帮助。当然，that还有其他的一些用法，需要我们在学习的过程中不断地积累和总结。希望我们一起加油！！