本文讲解了16种It做主语时的英语重点句型，希望同学们能够全部掌握住。
第一组：
1. It`s no good/use doing something: 做某事没有好处/用处
It`s no good watching too much TV;
看太多的电视没有好处。
2. It is worth doing something: 值得做某事
It is worth reading again.
值得再读一遍。
3. It is a waste of time doing something：做某事浪费时间
It is a waste of time discussing the problem with him.
和他讨论这个问题是浪费时间。
第二组：
4. It is （high，about）time for somebody to do something:
到了做某事的时候了。(high ：加强语气，表示立刻做某事， 时机已经成熟)
It is high time for you to do your homework.
现在是你做作业的时候了。
5. It is time that从句：该某人做某事的时候了
此句型为虚拟语气句型，含有该事早该去做而未做，现在去做似乎都为时已晚的意思。从句中的谓语动词有两种形式，用动词的过去式( be 用 were )，或者用 should + 动词原形（should不能省略)。
（1）it is time that Children went to school.
（2）It is time that Children should go to school.
孩子们该上学了。
第三组：
6. It is the first/second … time that:第一次/第二次做某事
（1）当系动词是is 时，that从句使用现在完成时；
（2）当系统词是was时，that从句使用过去完成时；
It is the second time that I have been to Beijing.
这是我第二次来北京。
It was the first time that I had read the book.
这是我第一次读这本书。
7. It is + some time + since从句（一般过去时，通常为瞬间动词）；
It has been + some time + since从句（一般过去时，通常为瞬间动词）
It is three years since his grandma died;
It has three years since his grandma died;
他祖母已经去世了三年了。
第四组：
8. It takes somebody sometime to do something;花费某人时间做某事
It takes me three hours to work out this problem.
我花了三个小时解出这道题。
9. It is one`s turn to do something: 轮到某人做某事了
It is my turn to do cleaning today.
今天轮到我打扫卫生了。
10. It is up to somebody to do something : 由某人做主做某事；
It is up to you to teach their children manners.
由你来教他们的孩子礼貌。
第五组：
11. It is a pity (a shame, an honor, a good thing, a fact, a surprise ...) that从句：
that后的从句一般用虚拟语气（should + 动词原形），should可省去．表示出乎意料，常译为“竟然”。没有这种意义时，则不用虚拟语气。
It is a pity that such a thing (should) happen to you.
真是遗憾, 这样的事竟然发生在你身上。
It is a pity that he couldn`t attend the party.
他不能参加这个聚会，真遗憾！
12. It is said (reported, learned, believed, thought, known, told, hoped.....) that 从句.
常译为“据说（据报道，据悉．．．）”。
It is said that he has been admitted into a key university.
据说他已被一所重点大学录取。
It is reported that more and more students are addicted to playing net games
据报道，越来越多的学生沉迷于玩网络游戏。
13. It occurred to somebody that: 某人突然想起某事
It suddenly occurred to me that I hadn"t finished my homework.
我突然想到，我还没完成作业。
14. It + seems /appears/ happens /doesn ’ t matter /that... 好象 / 碰巧 / 重要 / ……
It seems to me that she ’ s right.
在我看来， 她做得对。
It appears that you have made a mistake.
似乎你弄错了。
It happened that I have something important to attend to that afternoon.
碰巧那天下午我有要事要处理。
It didn ’ t matter that our best player was injured-- we still won. 我们最优秀的队员受伤也没有关系， 依然赢了。
15. It looks (seems) as if ….
该句型中 it 无意义，as if 引导一个状语从句。
常译为“看起来好像 …”，如果与事实不相符，则使用虚拟语气。
It looks as if he is ill.
看来他好像病了。
It looks as if he were ill.（虚拟语气）
It seemed as if he were dying.（虚拟语气）
他好像快死了。
16. It is/was + 被强调的部分 + that/who + 其他： 强调句型
当被强调的部分是人时，可以使用that/who
It was he who read three books in the library yesterday.
昨天是他在图书馆读了三本书。
