北京朗阁海外考试研究中心
雅思对于写作的评判遵循global scoring的原则，如何提高句子的表现力，使考官能够impressive, 来提升自己的写作level当属学生感困惑之处，往往加倍的努力并不一定收效显著，还会在具体写作时捉襟见肘，错误叠出，这大部分是由于平时积累欠缺，对西方写作风格掌握不够的缘故。针对大部分考生备考时间短的现实，朗阁海外考试研究中心分析认为，除了加强练习不同的写作话题，积累观点，储备功能性套句以外，若能从定语从句的角度具体细致地进行练习，也不失为良策。因为它具备如下特点：
一、简单易操作
定语从句是中学语法内容中的重要部分之一，大部分同学只是对其用法模糊而已，不够细致和确定而已，不存在对根本概念的输入难度。但正因为如此，也使得考生容易掉以轻心，此时教师应充分强调其重要性。
由于大部分学生手中都有现有的语法书，学生只需重点关注相应定语从句的章节即可，简单易行。笔者以下列‘常用that 不用which’的用法举例，归纳为11点，方便学生在练习时查对。
1. 当先行词为all, little, much, few, everything, none等不定代词时关系代词用that而不用which.
I will tell him all that you told me at the ball.
There are few books that you can read in this book store.
2. 当先行词既有人又有物时，关系代词用that, 不用which.
He asked about the factories and workers that he had visited.
3. 当先行词有形容词修饰时，关系代词用that, 而不用which.
This is the best novel that I have ever read.
Guilin is one of the most beautiful cities that I have ever visited.
4. 当先行词有序数词修饰时，关系代词用that, 不用which.
The first sight that was caught at the Great Wall has made a lasting impression on him.
5. 当先行词被the only, the very, the same, the right等修饰时，关系代词用that, 不用which.
That is the very thing that we can do.
It is the only book that he bought himself.
6. 当先行词被all, every, any, much, little, few, no等修饰时，关系代词用that, 不用which.
You can take any room that you like.
There is no clothes that fit you here.
7. 当主句是以which开头的特殊问句时，定语从句关系代词一般用that而不用which.
Which of the books that had pictures was worth reading?
8. 在强调句型"It is ... that ..."中，只用that, 不用which.
It is in this room that he was born twenty years ago.
9. 在"such (the same) ... as ..." 句型中，关系代词要用as, 而不用which.
We need such materials as (not which) can bear high temperature.
10. 表示"正如...那样"，"正像..."之意时，用as, 不用which.
Mary was late again, as had been expected.
11. As引导的定语从句可以放在主句前面，也可以放在主句后面或主句中间，而由which引导的定语从句只能放在主句后面。
As we all know, oceans cover more than 70% of the earth.
二、效果显著
定语从句能比较显著地彰显出写作者的实力。一个恰到好处的定语从句，能体现出作者对整体句子较为的掌控能力，并增强句子的紧凑感。
三、便于修正
由于定语从句并非语法难点，学生们在练习时也可进行peer correction, 方便易行。
四、方便示范
在朗阁海外考试研究中心老师撰写的雅思范文中，很容易找到相应的定语从句范文例句，方便进行讨论和仿写。
