一、引言
在看学生的雅思写作文章过程中，总会看到这样的文字，“College graduates are difficult to find jobs. ”，“Parents realise the needs of their children is extremely important. ”，“Students cannot focus on their study because of tiredness is a fact. ”， “Clearly, rush hours emerges in the early morning as well as early evening which is most busy in a day as a whole in London.” 这几个句子，虽然长短不一，结构不同，话题各异，但是，学生对形式主语it的驾驭能力的欠缺，是可见一斑的。
二、形式主语
（一）什么是形式主语
作为形式主语的it并无实际语义，是为满足语法上的需要，避免句子头重脚轻，它代替的是句子的逻辑主语。
（二）形式主语it所在的句型类别
1、作不定式的形式主语
（1）句型
It is + a pity/a pleasure + to do sth.
It is + wrong/right/wise/cruel/naughty/selfish + of sb. + to do sth.
It is + necessary/hard/important/difficult/possible/common + for sb. + to do sth.
（2）雅思范文写作实例
A. Beyond this, it is also of paramount importance to use theaters and museums as the “social classroom" of culture and history education.
B. I think it is by no means pointless in any way to try to keep traditions alive with technology (Cambridge;3,;P162,;Task;2)
C. It is difficult to say who has the rightto judge whether children working is “wrong” or “valuable”. (Cambridge;3,;P164,;Task;2)
D. it is important to remember that need to develop skills other than intellectual ones and …(Cambridge;3,;P168,;Task;2)
E. Finally, I think that it is also important to remember that children need to relax as well as work. (Cambridge;3,;P168,;Task;2)
F. Because people interpret happiness for themselves in so many different ways it is difficult to give and definition that is true for everyone.(Cambridge;4,;P165,;Task;2)
G. It is quite common these days for young people in many countries to have a break for studying after graduation from high school.(Cambridge;5,;P165,;Task;2)
H. They may think that it is better to continue in a particular job or to do sth completely different from a university course. (Cambridge;5,;P165,;Task;2)
据本人统计，剑桥官方的雅思真题（剑3—剑8）几乎每一篇Task2考官范文中，都有所使用，甚至在有的文章中出现三次之多。
（3）学生写作实例
实例1
Many people if not most are strong believer in the claim that regard children go to work as completely wrong, while others hold the opposite opinion.
修改建议：it; is; completely; wrong; for; children; to; go; to; work.
实例2：They have to complete their homework conscientiously within limited time and difficult to discover the problems in studies.
修改建议：Thus it is difficult to discover their problems in study.
实例3：College graduates are difficult to find jobs.
修改建议：It is difficult for college graduates to find jobs.
实例4：Parents realise the needs of their children is extremely important.
修改建议：It is extremely important for parents to realise the needs of their children.
It is extremely important that parents realise the needs of their children.
2、作动名词的形式主语
（1）句型
It is + (no) use/good/useless/a waste of time/energy/efforts + doing sth.
It is + good/useless/hard/foolish/enjoyable/worthwhile + doing sth.
（2）雅思范文写作实例
A. For instance children usually pay attention to match their clothing and toys in fact it is really worth competing thing that their study is being ignored.
B. Some parents believe that it is no use having second education for their kids.
（3）学生作文实例
实例：Particular countries and individuals deals with environmental issues are no use.
修改建议：It is no use dealing with environmental issues by particular countries and indivuduals.
3、作主语从句的形式主语
（1）句型
It is + (adj) n./(adv.) adj./(adv.)v-ed + that……
It + seems/happens/appears/matters//strikes/occurs(突然想起) + that……
It is + said/reported/believed/(universally/widely) accepted/announced/estimated/acknowledged + that……
It + must be admitted/stressed out + that…/It + cannot be denied + that….../It + can be foreseen + that……
It + goes without saying + that…
（2）雅思范文实例
A. It is an understandable fact that many employers may prefer to use the services of children simply to save money by paying them less than adults and it is this type of exploitation the should be discouraged. (Cambridge;3,;P164,;Task;2)
B. Admittedly, it is common sense that a person without cooperative spirit will be difficult to survive in the modern society.
C. Unfortunately, it is not always the case that new things are promoted because they have good mpacts for the majority of people.(Cambridge;6,;P168,;Task;2)
D. It is clear from the data given that there are some significant differences in spending habits in Europe. (Cambridge;3,;P161,;Task;1)
E. It goes without saying that it pays to keep early hours.
F. Take holding an Olympic games as an example it is no doubt it will take millions of money to build stadiums.
G. A more dramatic rise is predicted between 2030 and 2040 in Japan by which time it is thought that the proportion of elderly people will be similar in the three countries. (Cambridge;5,;P162,;Task;1)
H. It seems that the experiences we have in life are so unpredictable and so powerful that they can boost or overide other influences,…(Cambridge;5,;P169,;Task;2)
（3）学生写作实例
实例
It is quite obvious/evident/apparent that the quantity of families who tends to go outside and infuse fresh oxygen into their lungs is growing steadily.
实例2
It is universally acknowledged that the bestway to arouse people’s love to our nature who has devoted herself too much to human being’s development while has received barely anything till now is to let them see the beauty of hers by themselves.
这是XVCC23强化班里一位基础较好的学生的写作实例，其中的语法、措辞方面的错误已经进行了修改。
实例3：Clearly rush hours emerges in the early morning as well as (in the) early evening which is most busy/the busiest in a day as a whole in London.
修改建议：这个句子的结构应该是无可厚非的（语法就不说啦），但是，按照雅思评分的标准，句式稍微做一下调整，会更漂亮：
It is clear that rush hours emerge in the early morning as well as in the early evening which is most busy/the; busiest in a day as a whole in London. 或者改成
It is demonstrated that rush hours emerge in the early morning as well as in the early evening which is most busy/the busiest in a day as a whole in London. 这样一个小小的调整，其句子修改前后的效果是显而易见的。
（三）it作形式主语的特征分析
根据以上对it作形式主语的句型结构的解析，对雅思写作范文、尤其是官方考官范文的分析，以及对学生写作过程中出现的it使用状况的详细解读可知：相比较于名词性从句、定语从句、状语从句的复杂性和多边性，it作为形式主语的句式结构可谓简明扼要，学生掌握起来应该说是得心应手的。
（四）不能正确使用it形式主语的原因
在信息编排时，英语句子遵循“end focus”的原则，即旧信息在前，新信息在后“old information+new information”；但是，当句子主语结构较长，容易使句子产生“head weight”的感觉时，句子结构则遵循“end weight”的原则，即，把较长的主语全部置于句子尾部。前面空掉的主语位置用it来代替，担当形式主语的功能。
而汉语并不具有这类明显的特征，学生对英汉两种语言结构差异知之甚少，或者略有所知，在真正的运用中，也未必能够正确的体现出来。多数学生都本着汉语式的思维，一遇到“某人做某事是怎么样的/是什么”就习惯性地写成it"
三、总结
建议学生在雅思学习中，采取步步为营的四步走战略战术，循序渐进：首先，记住句型结构；其次，模仿写作；之后，进行独立创作；最后，形成属于自己的模板句型。作为雅思写作学习中可控制的因素，我们可以培养句式运用的习惯，使习惯称为自然。为了我们雅思的学习这个努力是值得的，it pays in the long run.
