it /it/ pron. 1. 指刚提到的东西（可以是具体的，也可以是抽象的）：What a beautiful baby — is it a boy? 多漂亮的娃娃—是男孩吗? If I can stop her coming to you, I shall do it. 如果我能阻止她到你处，我会干的。2. 表示时间、天气、距离等：What is the date? It is the third of May. 几号了?5月3日。 I think it’s going to rain. 我想天快下雨了。 How far is it from your office to the bank?从你办公室到银行有多远? 3. 用作形式主语，可代表后面的不定式、v-ing或从句：It’s easier to be said than done.说起来容易做起来难。It takes two to make a quarrel.［谚］一个碗不响，两个碗丁当。It’s no use/good saying any more about what I think. 再说我考虑的事情就没用处(好处)了。In this situation it is better that he do it. 在这种情况下最好他去干这件事。It is said (believed, thought) that he’s criminal. 据说(信)他犯罪了。 4. 作形式宾语可代表后面的不定式或从句：I regard it important to finish this job on time.我认为准时完成这项工作是很重要的。I took it for granted that you would stay with us. 我满以为你会跟我们在一起的。 5. 用来强调句子的主语、宾语、状语等：It was she who was wrong. 是她错了。It was the President that Jean shot yesterday. 琼昨天刺死的是总统。It was on Monday night that all this happened. 所有这一切都是在周一夜里发生的。［考句］It was in the 1960’s that the trade between the two countries reached its highest point.就在20世纪60年代，两国之间的贸易达到了最高点。［考句］It was from Stephen that she first heard of the man referred to as a specialist. 她是从斯蒂芬那儿第一次听说被称为专家的那个人。［考句］ When I try to understand what it is that prevents so many Americans from being as happy as one might expect, it seems to me that there are two causes.当我试图搞清究竟是什么使得美国人不能像其期望的那么幸福时，我似乎找到了两个原因。6.表示谁做某动作：Who is it? It’s me.是谁?我。What’s that noise? It is only the dog.怎么那么大声音?就那狗弄的。
its /its/ pron.它的(it的形容词性物主代词，定语): The book has lost its cover. (注意与it’s的区别，it’s是it is、it has的缩略形式)
itself /itˈself/ pron.它自己（作宾语和用作强调）: The cat’s washing itself.猫在洗脸。The dog found the food itself. 狗自己找到了食物。by itself单独地，独立地: The tree stands by itself in the garden. 那棵树孤零零地立在花园中。Put it by itself. 把它单独放。in itself本质上；就其本身而言：Some would say bringing up a family was a full-time job in itself.有人说养育子女本身就等于一份全职工作。
