1、It 作形式主语结构总结 当句子的主语是不定式、动名词或主语从句时，常常可以用 it 作形式主语，而把 真正的主语移到句子后部。 用 it 作形式主语的好处是避免句子由于主语太长而显 得头重脚轻。 1.it 在句子中做形式主语的各种用法 1) it 作不定式的形式主语作不定式的形式主语 a) it + be + 形容词 + 不定式 It is difficult to get there before dark. 天黑以前赶到那里很困难。 It is better to get up early. 早起会更好。 b) it + be + 名词 + 不定式 It was his duty to
2、attend to this matter. 处理这个问题是他的责任。 It is the file systems job to manage writing data between the disks and memory. 在内存和磁盘上管理数据是文件系统要处理的东西。 c) it + 动词 + 宾语 + 不定式 It takes a lot of effort to recover the system. 恢复系统不是一件容易的事情。 It makes me sad to hear that you have to go away. 听说你一定要走，我很难 过。 d) it + be
3、 + 介词短语 + 不定式 It is against the law to steal. 偷窃是犯法的。 2) it 作动名词的形式主语作动名词的形式主语 a) it + be + 名词 + 动名词 (常用的名词有 no good, no use, a waste, a wonder 等) Its a wonder meeting you here! 在这里遇见你真是个奇迹！ Its no use doing a lot of work without thoughtful planning. 没有考虑周到的计 划而做一大堆工作是没用的。 b) it + be + 形容词 + 动名词 It
4、was very difficult getting everything ready in time. 要及时做好一切准备很 难。 Is it worthwhile hating each other over such a trifle? 为了这么点事儿，你俩至 于结冤吗？ c) 其他情况 It doesn t matter putting these two files together. 把这两份文件放在一起没关 系。 It doesn t make any difference my being here. 我是否在这儿并不能改变什么。 （注:这里 my 为动名词的逻辑主语） 3)
5、it 作主语从句的形式主语作主语从句的形式主语 a) it + be + 形容词 + 从句（It is natural that 很自然 It is strange that 奇怪 的是） It is uncertain whether he can come to Jennys birthday party or not. 他来不来参加简的生日派对，这个不确定。 It is clear that the chosen pattern is not the correct one. 显然， 所选择的图式是错 误的。 It is doubtful whether this method is m
6、ore scientific. 这个方法是否更科学值得 怀疑。 b) it + be + 名词 + 从句(It is a fact that 事实是 It is an honor that 非常 荣幸 It is common knowledge that 是常识) It is a pity that we shall have to leave tomorrow. 我们明天必须离开，真是遗憾。 It is a complete mystery what caused the accident. 是什么引起这场事故完全是个 谜。 c) it + 动词 (+宾语或状语) + 从句 It matt
7、ers little who does it so long as it is done. 只要事情做了，谁做都行。 It happens that his sister is a close friend of mine. 碰巧她姐姐是我的一个好朋 友。 d) it + 动词的被动语态 + 从句 （It is reported that 据报道 It has been proved that 已证实） It is said that the rhythm of tides is affected by the moon. 据说潮汐的涨落受月 亮的影响。 It is estimated tha
8、t the output will increase by 20% this year. 今年预计产量将提高 20%。 e) it is 不及物动词从句 It seems that 似乎 It happened that 碰巧 It seemed that he didnt tell the truth. 似乎他没有讲真话。 It happened that I was out when he called. 碰巧，他打电话的时候我在外面。 f) it + 介词 + 从句 It is out of question that Chinas economy will keep growing f
9、or 40 years. 中国经 济增长 40 年应该不成问题。 2. It 作形式主语和 it 引导强调句的比较： It 作形式主语代替主语从句， 主要是为了平衡句子结构， 主语从句的连接词没 有变化。 而 it 引导的强调句则是对句子某一部分进行强调， 无论强调的是什么成分， 都 可用连词 that。被强调部分指人是也可用 who/whom。例如： It is a pity that you didnt go to see the film. 你没有去看这个电影，多可惜啊！ It doesnt interest me whether you succeed or not. 对于你是否成功，
10、我并不感兴趣。 It is in the morning that the murder took place. 凶杀案发生的时间是在早上。 It is John that broke the window. 打碎窗户的是约翰。 Exercises: 对我来说学习英语是很容易的。 对与那个聪明的男孩来说游泳是很困难的。 建议每个高中生去看这部电影。 照顾好每一个孩子是我的职责。 每人知道她长大后想干什么。 在这里遇见你真是个奇迹！ 他来不来参加简的生日派对，这个不确定。 我们明天必须离开，真是遗憾。 你已经 18 岁了，这是一个事实。 在哪里开派对，还没有确定。 _everything in
11、the world changes was often a theme in poetry. _will preside at the meeting has not been decided yet. It is a mystery_you are going to deal with it. _you can succeed or not depend on how hard you work at it. It doesnt matter_you pay in cash or by credit card in this store. It is amazing_there are more than 8,000 statues. It is no surprise_our team has won the game.
