It’s ten past six. (指时间)
It’s warm at the moment. (指天气) It’s two miles to the beach. (指距离)
Being a parent is not always easy, and being the parent of a child with special needs often carries with it extra stress.
（指代 being the parent of a child）
--- There is still a copy of the book in the library. Will you go and borrow it? （指代 a copy of the book）
--- No, I’d rather buy one in the bookstore.(2007）
It is/was + 被强调部分+ that + 其他（当被强调部分是人时也可以用 who）。此句型用于强调除谓语之外的任何成分。
It was not until he came back from Africa that year that he met the girl he would like to marry. (强调 not until 时间状语从句)
--- I’ve read another book this week.
--- Well, maybe it is not how much you read but what you read that counts. (强调由 not… but 连接的两个主语)
- it 用作形式主语，真正的主语是不定式、-ing 形式和 that 从句。
其句型为：It is + 形容词/名词/过去分词+ to do sth. \ doing sth. \ that clause. The doctor thought it would be good for you to have a holiday.
It is no use arguing with a person like him.
It is reported that the earthquake has killed 20,000 people in Japan.
- it 用作形式宾语，可以带形式宾语的词有：think, believe, feel, make, find, imagine, consider 等。
The fact that she was foreign made it difficult for her to get a job in that country. We have made it clear that we are strongly against smoking in the office.
(1). It is(was) the first (last, second, third…) time that sb. has (had) done sth.
It’s the first time that he has been to Australia, isn’t it? (2). It is (has been ) 一段时间 since sb. did sth.
表示 since 从句中的动作或状态结束时到现在的时间，也就是说延续性动词表示否定意义，瞬间动词表示肯
It is three years since I was a teacher. 表示我不当老师有三年了。
It is three years since I began to be a teacher. 表示我当老师有三年了。
- It will (not) be 一段时间 before … 表示”还要多久……才……(不久……就……)” John thinks it won’t be long before he is ready for his new job.
If I can help it, I don’t like working late into the night. 如果我有办法的话，我也不想工作到深夜。
I’d appreciate it if you would like to teach me how to use the computer.
I like it when you do that. 我喜欢你那样做。
When it comes to getting things done, he’s useless. 一涉及到做事，他便不中用了。
As someone puts it, practise makes perfect. 正如某人所说的，熟能生巧。
Can you see to it that the fax goes this afternoon? 你保证今天下午就把传真发出去，行吗？
Depend on it that we won’t give up. 请相信，我们决不会放弃。