5.It is/was v-ed that clause=sb is/was v-ed to do sth

(用于这种句型的动词常为say, report, think, believe, hope, expect, agree, accept, decide, determine, intend, plan, understand, know)

It is said that the couple have gotten divorced.(=The couple are said to have gotten divorced.)

4. It is +n. + v-ing.

It’s no use/good doing sth.

It’s (well) worth doing sth.

It is no use crying over spilt milk.覆水难收

3．It +will be／is／was+adj+v-ing。

It's bad playing in the street．在街上玩是没好处的。

Is it any good trying again？再试一次有用吗？　

2. It is / was +n. + (for /of sb ) to do sth/that clause

注意：这一句式中的连系动词be也可换用其它连系动词，如feel等。

It's a good habit to get up early and go to bed early．早睡早起是好习惯　

It must be great fun to fly to the moon in a spaceship．乘宇宙飞船飞往月球一定很有趣

It feels strange to have a twin sister．有个孪生姐妹感觉很奇怪　

It’s no secret that the president wants to have a second term at office.

(It’s) no wonder that he is angry.

英语中常常见到某个句子以it开头，it与其后面的动词不定式短语、动名词短语、名词性从句等相呼应，以表达一个完整的意义。这是一种习惯表达法，这样的句式可避免句子显得头重脚轻

1．It+is／was+adj.+(for／of sb)+to do sth/that clause

对于这个句型中究竟用 for还是用of，一般遵循这样的规则：如果形容词仅仅是描述事物的形容词，如：difficult， easy，hard，important，dangerous等用for；如果形容词是描述不定式行为者的性格、品质的，如：kind，good，nice，clever等则用of

It is interesting to play with snow in winter．　 　　冬季里玩雪是很有趣的。　

It's important for us to keep the water clean．　　 保持水质清洁对我们来说是很重要的。　

It's very kind of you to say so．　　　　　　　　 你这样说真是太好了

It is certain that he will come．　　　　　　　　 他一定会来

It's true that he may fall behind the other students．他真的可能落后于其他同学

It is strange that he should say so．　　　　　　 他居然这么说，真是奇怪

3．表示自然现象。　

Sometimes it snows and the land is all white．有时下雪，大地一片白。　

It is very quiet here at the moment．眼下这儿很安静。

2．表示距离。　

It's half an hour's walk from my home to the school．从我家到学校步行得花半小时时间。　

　-Where's the farm，Li Lei？Is it far？李雷，农场在哪里？远吗？

-No，it's quite near．不，(距)离这很近。

1．表示时间。　

-What time is it？几点钟？　

-It's ten．十点钟。

It's summer in Australia now．现在澳大利亚是夏天。

特别注意it用于表示时间时还常见于以下三个句型中：

(1)It's time(for sb．)to do sth．／It's time for sth． “是(某人)该干……的时间了”、“到……的时候了” 　

It's time for supper／to have supper．是吃晚饭的时候了。

I think it's time for us to start the lesson now．我想现在是我们开始上课的时候了。　

(2)It is ／has been +时间段+since +一般过去时

It was +时间段+since+过去完成时

“自从……以来已过了……(时间)”

It has been two weeks since we met last．自从我们上次相遇以来，两个星期过去了。

It's three years since he came here．＝It has been three years since he came here．

＝He has been here for three years．他到这里已经三年了。

注意：It is/has been+时间段+ since …continuous v-ed(延续性动词) 某动作已有多长时间不发生了

It's 10 years that he lived here　

(3)it’s (about/high) time that sb. did sth. (正是)该某人做某事的时候了(这是一个虚拟语气，表示对现在事实相反的虚拟语气)

It’s high time that we went to school.

(4)It is the x-th time (that) sb have done sth

It was the x-th time that sb had done sth这是某人第几次做某事了

It's the third time that he has failed the driving test.

It was the second time that he had seen the film.

　(5)It was(not) +时间段+before +一般过去时 “过(不)了多长时间某动作发生了”

It will be +时间段+before+一般现在时 “过多长时间才…”

It was not long before they arrived.

It will be several years before we meet again.

4．在回答用指示代词表示人的特殊问句时，常用it指人　

　-Who's that？那人是谁？

　-Is it Kate？是凯特吗？

-Yes，I think you're right．It's Kate．是的，我想你说对了，是凯特。　

3．指代性别不详的婴幼儿或在不计较性别时，也可用it来指人。

The child smiled when it saw its mother．这小孩一见到母亲就笑了。

I don't know who it is．我不知道他是谁。

注意：看到这样的句子(或听到这样的话)时，要想一想，不要一看到it就把它译成“它”。)