(壹) 引言段中的應用
1. Globalization
Globalization—the international spread of products, ideas and information—is bringing the world closer together. But globalization is not a new concept. For thousands of years，nations have roamed the earth in search of new markets and new sources of raw materials for their own industries.
關於“全球化”這個名詞，考生並不陌生，但是如何用合理的語言來賦予它壹個含義，這並非易事，上述的引言段就很好地做到了這壹點，先是從字面上詮釋了“全球化”的定義，進而又從實際生活角度賦予了它另外壹層含義。
2. Telephone/Mobile phone
Imagine using smoking signals，carrier pigeons or riders on horseback to send an important message. Although those methods may sound strange，years ago people used them to communicate. Today，all a person has to do is pick up a telephone/mobile phone.
對於電話這壹現代通訊工具，地球人都知道它是幹嘛的，不過呢，我們可以從對於電話功能的定義上做文章，同樣也可以賦予它壹個生動的含義，並且壹下子可以吸引讀者眼球。
3. Studying abroad
Every year，students around the world leave behind the comforts of home to pursue a study-abroad experience in a foreign country. While many would say that studying abroad is advantageous，some would argue otherwise.
出國留學同樣是壹個非常熟悉的話題，若直接用字典上的定義直接去解釋它顯然多此壹舉，因此，我們不妨從側面突破，通過引入大量學生出國留學的事實和目的來詮釋這個再也不能熟悉的話題，同樣可以起到很不錯的效果。
4. Success
As Thomas Edison once said，“If you wish to succeed，you should use persistence as your good friend， experience as your reference，prudence as your brother and hope as your sentry. ”This essay is going to look at factors that constitute success.
(二) 主體段中的應用
1. Some people think that universities should provide graduates with the knowledge and skills needed in the workplace. Others think that the true function of a university should be to give access to knowledge for its own sake，regardless of whether the course is useful to an employer. What，in your opinion，should be the main function of a university? (劍七Test 4)
以下是此題目壹篇範文的第2個主體段：
However, reaching the conclusion that other functions，such as giving access to knowledge for its own sake，are no longer important is biased. For hundreds of years，especially in the west，the undergraduate education is，indeed， a liberal education，which means the undergraduates learn a wide range of curriculums such as psychology， economics， politics that has no direct relations to jobs. The upsides of this is that it firstly enables students to become broad-minded and help them lay a solid theoretical foundation，then they will be able to choose the most appropriate field based on their own interests for further studies.
這個段落的論述的中心是大學以傳授知識本身為目的，作者使用了“通才教育”這個在西方國家非常流行的教育方式為佐證，在給出“通才教育”定義的本身，又用定語從句補充到了和題目第2個論點間的關系，從而進行了有力的對比，深化了段落中心。
2. Education
When people leave school，they wish they could breathe a sign of relief and leave learning behind. However，learning should last a lifetime. You exercise your body to stay strong，and you should exercise your mind to stay sharp. ……
在這個關於教育的話題中，作者在論述時用終身教育的好處來詮釋教育的長期性和必要性，從而為下文的擴展作了很好的鋪墊和過渡。
3. School should teach children academic subjects which will be beneficial to their future careers. Therefore，other subjects such as music and sports are not important. To what extent do you agree or disagree with this opinion?(08年5月22日A類考題)
Academic subjects，such as reading and writing，play a vital role in the education system. Apart from activating creativity and imagination，it helps students lay a solid foundation of knowledge. Some might say that academic subject is to a student as a rifle is to a soldier，without which he is unable to fulfill his mission……
在這個主體段中，作者在開頭便舉出了壹些學術課程的具體內容，從而給讀者壹個概念，同時也展現了作者對題目的解讀能力。接下來我們再來看壹個相似的用法：
4. Why have not alternative energies already replaced fossil fuels?
在這篇分析型大作文裏，作者通過對化石燃料和可替代燃料的對比，突出了前者的優點，也揭示了後者的不足。通過將壹個名詞範圍中的具體例子舉出，是下定義的另外壹種詮釋。
綜上所述，下定義可用於議論文的開頭或者主體段裏，但是它壹般不適用於用在結尾段中。除了字典上的定義外，朗閣海外考試研究中心建議考生還可以從這個名詞或短語的功能、目的、包含的具體例子等方面賦予它含義，這些方式都屬於下定義。
雅思作文網(/ielts/zuowen/)歡迎您再來拜讀《“下定義”在議論文中的用途》壹文.