代词it基本用法小结
人称代词it可以用来代替一个名词、一个短语、一个从句或一个句子，以避免它们在句中的重复。这时它可以指提到过的，也可以指未提到过的，在句中作主语或宾语。
(1) 替代刚提到过的同一事物
This is our new car. I bought it yesterday. 这是我们的新车。我昨天买的。
(2) 指动物或不考虑性别的婴儿
Where is the cat? It’s under the bed. 猫在哪？它在床下面。
The baby cried when it was hungry. 这婴儿饿时就哭。
(3) 在情景中确认某人或事物
Who is it? It’s me. 是谁？(问敲门人) 是我呀。
Who’s it over there? It’s the milkman. 那边那人是谁？那是送牛奶的
What’s this? It’s a map. 这是什么？这是张地图。
(4) 指代前句或后句所述的情况
He smokes in bed and I don’t like it. 他在床上抽烟，我不喜欢他这样。
When the factory closes, it will mean 500 workers will be out of work. 工厂一旦关闭, 那就意味着要有500工人失业。
It would be ideal if you could join us. 如果你能和我们合作，则太好了。
(5) 指时间、距离、天气或环境等
What time is it? It’s seven o’clock. 几点了？7点。
It’s time for supper. =It’s time to have supper. 是该吃晚饭的时候了。
It’s about 50 kilometers from here to my home. 从这儿到我家约有五十公里。
It is snowing. 正在下雪
It was very quiet in the garden. 公园里很寂静。
(6) 用于笼统地谈论某种情况
I cannot help it. 我也没办法。
(7) 指最好的或最渴望得到事物
He thinks he’s it. 他一直以为自己是最佳人选。
That steak was really it! 那牛排真是不错！
We’ve been looking for a house for months and I think this is it. 我们找房子已经找了好几个月了, 我看这所就是我们要找的。
it用作形式主语特殊句式小归纳
it用作形式主语有不少非常有用的句式，比如以下一些就值得注意：
1. 用于it seems (appears) that…句式。如：
It seems that he knows everything. 他好像什么都知道。
It appears that we may be mistaken. 看来我们可能弄错了。
但是，英语一般不说it looks that…，可改用it looks as if…。如：
It looks as if we’ll be late. 我们似乎要迟到了。
2. 用于it happens (occurs) that…句式。如：
It happened that I was standing next to him when he collapsed. 他倒下的时候我恰巧站在他旁边。
It didn’t occur to him that she would refuse his invitation. 他没有想到她会拒绝他的邀请。
3. 用于it follows that…句式。如：
He is wrong, but it does not follow that you are right. 他错了，但并不能由此推断你是对的。
She’s not in the office but it doesn’t necessarily follow that she’s ill. 她不在办公室, 并不见得就是病了。
哪些从句作主语时可用it作形式主语
原则上说，it用作形式主语可以代替下列从句：
1. that从句
It is quite clear that he has read the book. 很显然，他读过这本书。(HM)
2. what从句
It doesn’t matter what he says. 他说什么没关系。(HM)
It was clear enough what he meant. 他的意思是很明显的。
3. who从句
It hasn’t been decided who will be sent to work there. 还没决定将派谁到那里工作。
4. how从句
It struck her how gentle he was being. 她深深感到他多么温存。
5. when从句
It hasn’t been made clear w hen the conference is to take place. 会议什么时候召开还没有宣布。
6. where从句
It’s not known where she went. 她到哪里去了没人知道。
It did not matter much where he lived. 他在哪里住都没有关系。
7. why从句
It was clear why he had asked for a conference. 他为什么要求召开会议原因很清楚。
8. whether从句
It makes little difference whether we go or stay. 我们去还是留没有多大差别。
It’s not yet settled whether I am going to America. 我去不去美国还没定。
it用作形式主语代替动名词主要用于哪些句式
it用作形式主语代替动名词的用法主要见于以下句式：
1. It is no use (no good, fun, great fun, a new experience, a great honour, etc) doing sth。如：
It is no good talking. 空谈是没有用的。
It’s fun working for him. 为他工作很有意思。
It’s great fun sailing a boat. 扬帆驾舟十分有趣。
It’s no use shouting at him—he’s deaf. 向他叫喊是没有用的——他耳聋。
It has been a great honour your coming to visit us. 你来看望我们是极大荣幸。
2. It is good (nice, useless, interesting, pleasant, tiring, etc) doing sth。如：
It is useless speaking. 光说没有用。
It was pleasant sitting there. 坐在那里很愉快。
It’s so nice sitting here with you. 和你坐在一起真是愉快。
It’s good hearing English spoken. 听到人讲英语，我很高兴。
It’s terribly tiring working late like this. 这样干到深夜是非常累人的。
3. it is worth while doing sth。如：
It’s worth while doing the work. 这项工作值得做。
Do you think it’s worth while quar relling with me? 你认为和我吵值得吗?
