1.指上文提到的東西
Look at the bird.It always comes to my window.瞧那只小鳥,它老飛到我的窗口來。
【比較】
①I have lost my umbrella;I’m looking for it.(it特指“同名同物”)
②I have lost my umbrella;I think I must buy one.(one泛指“同名異物”)
2.指不知性別的child和baby
The child smiled when it saw its mother.小孩見到母親就笑了。
What a beautiful baby it is! 多漂亮的寶寶呀!
3.指未出場身份不明確的人
— Listen.Someone is crying.聽,有人在哭。
— Oh,it must be Mary.噢,一定是瑪麗。
— Who’s knocking at the door? 誰在敲門?
— It must be the postman.肯定是郵遞員。
4.指時間、天氣、環(huán)境、距離等
It is damp and cold,I think it’s going to rain.天氣又冷又潮,我認為可能要下雨。(天氣)
What day is it today? 今天星期幾?(時間)
It’s very noisy in the room.屋里噪音很大。(環(huán)境)
It’s 112 miles from London to Birmingham.從倫敦到伯明翰有112英里。(距離)
5.代替某些指示代詞或不定代詞
“What’s this?” “It’s a flag.” “這是什么?”“一面紅旗。”
“Whose book is that?” “It’s hers.” “誰的書?”“她的。”
Nothing is wrong,is it? 沒出啥事,是吧?
6.用于強調(diào)句中
It was my father who did the experiment in the lab yesterday evening.
昨天晚上是我父親在實驗室做實驗。(強調(diào)主語)
It was the experiment that my father did in the lab yesterday evening.
昨天晚上我父親在實驗室里做的是實驗。(強調(diào)賓語)
It was yesterday evening that my father did the experiment in the lab.
我父親是昨天晚上在實驗室做實驗的。(強調(diào)時間狀語)
It was in the lab that my father did the experiment yesterday evening.
我父親昨天晚上是在實驗室里做實驗的。(強調(diào)地點狀語)
7.作形式主語
Is it necessary to tell his father everything?
有必要把這一切都告訴他父親嗎?(代替不定式)
It’s no good sitting up too late.熬夜沒有好處。(代替動名詞)
It is quite clear that he has read the book.很顯然,他讀過這本書。(代替主語從句)
8.作形式賓語
They found it pleasant that they worked with us Chinese.
他們發(fā)現(xiàn)與我們中國人一起工作很愉快。(代替賓語從句)
He makes it a rule never to borrow money.他立志決不向別人借錢。(代替不定式)
I think it no need talking about it with them.我認為沒必要跟他們談。(代替動名詞)
I don’t like it that he’s so lazy.我不喜歡他那么懶惰。(代替that引導的從句)
I hate it when my mother asks me to eat eggs.
我討厭母親要我吃雞蛋。(代替when引導的從句)
9.用于固定搭配中
as it is 實際情況是 believe it or not 信不信由你
get it 明白了 it’s up to sb.由……決定
it all depends 看情況而定 make it 成功、做到
take it/things easy 不要慌 that’s it 就是這樣