1. It (so) happened(chanced) that +clause. 碰巧…

　　= sb. happened /chanced to do sth. = sb. did sth. by chance.

　　It happened that he was out when I got there.当我到那儿时，碰巧他不在。

　　= He happened to be out when I got there./ It chanced that he was out when I got there./ He was out by chance when I got there.

　　2. It seems/appears that sb. do/ be doing/ have done/ had done 似乎…, 好像…

　　= Sb. seems/appear to do/ be doing/ have done/to be done/to have been done

　　It seemed that he had been to Beijing before. 他好象以前去过北京。

　　= He seemed to have been to Beijing before.

　　3. It is / was+被强调的部分+that(who)+剩余的部分.

　　It wasn't until he came back that I went to bed. 直到他回来我才睡觉。

　　(一定要注意被强调句型中的谓语动词否定的转移)。

　　It was because he was ill that he didn't come to school today.

　　只因为他有病了今天没有来上学。(只能用because而不能用for, as 或since)

　　4. It is/was+表示地点时间/的名词+where/when +从句。

　　(注意本句不是强调句型，而是以where/when引导的定语从句。)

　　It was this house where I was born.请比较：

　　It was in this house that I was born.(后一句是强调句型。)

　　It was 1999 when he came back from the United States. 请比较：

　　It was in 1999 that he came back from the United States. (后一句是强调句型。)

　　5. It is / was said ( reported…)+that+从句. 据说/报道…

　　It was said that he had read this novel. 据说他读过这篇小说。

　　= He was said to have read this novel.

　　6. It is impossible / necessary/ strange…that clause.

　　(从句中的谓语用should+do / should have done，其形式是虚拟语气。)

　　It is strange that he should have failed in this exam. 真奇怪，他这次考试没及格。

　　7. It is + a pity/ a shame…that clause. (注意从句中的谓语动词用should do或

　　should have done的形式，但should可以省略。)

　　He didn't come back until the film ended. It was a pity that he should have missed this film.他直到电影结束才回来。他没有看到这部电影真可惜。

　　8. It is suggested / ordered/ commanded /…that +clause.

　　(从句的谓语动词用should do, 但should可以省略。)

　　It is suggested that the meeting should be put off. 有人建议推迟会议。

　　9. It is high time (time/ about time)+ (that) 主语+should do / did+其它。

　　是该做某事的时候了(从句中的谓语动词用的是虚拟语气。)

　　It is high time that we should go / went home. 我们该回家了。

　　10. Not only +特定动词+主语+谓语…but also+主语+谓语… 不但…而且

　　Not only did he learned English well but also he spoke French very well.

　　11. It is well-known that+从句。 众所周知

　　It is well-known that she is a learned(知识渊博) woman.

　　12. It is +段时间+since+主语+did. / It was +段时间+since+主语+had done.

　　It is five years since he left here.他已经离开这儿五年了。

　　It was five years since he had left here.(同上)

　　注意: It is five years since he lived here.他从这儿搬走已经有五年了。

　　13. It +谓语+段时间+before+主语+谓语.( before引导的是时间状语从句。)

　　It wasn't long before the people in that country rose up.

　　没有多久那个国家的人民就起义了。

　　It will be three hours before he comes back..三个小时之后他才能回来。

　　14. It is +形容词(possible, impossible, necessary等) +for+ sb.+ to do.

　　It is impossible for me to finish this work before tomorrow.

　　15. It is +(心理品质方面的)形容词+of + sb. +to do.

　　= 主语+ be + adj. +to do. (常用的有kind, stupid; foolish, good, wise等。)

　　It is kind of you to help me. =You are kind to help me.