在托福写作中是一种有用的“出字”工具，尤其是对那些面对闪烁的光标一筹莫展无从写起的同学，或是日夜挣扎在独立300字数线的盆友。如能勤快一点，记十个八个(独立作文题目涉及的)常用概念的定义，考试的时候凡能用到某个这样的定义句，噼里啪啦先打出来，看着这一两行甚至三四行文字，心里自然能踏实许多。因此，这样的句子就被称为“镇魂句”了。
常在托福独立写作的课程体系中讲到“下定义”这个工具，无论是开头(“天下大势”型)还是主体段落(“explanation”部分中的“下定义”工具)都能祭出这招，而且用的得当的话，效果非常不错，也可以有效填充文章内容。
整理这些定义的时候，原则是“用户友好型”，也就是常用、好懂、好记、难易适中。这些定义句的内容参考了字典、百科、网上资料等处的释义，但是删掉了过于技术化和学术化的描述，必要时调整和改写之。
“镇魂句”怎么用?
下面小托为大家整理了“镇魂句”——也就是定义句的list，其中，橙色粗体部分的就是这些常用概念名词(如telephone )，而整个句子就是对这一概念的定义。每个定义句的后面，有该句可能
“科技”定义：
Technology is the activity or study of using scientific knowledge for practical purposes in industry, farming, medicine, business, etc.
可能用到的题目：
Technology designed to make our life simpler actually makes our life more complicated.
“电话”定义：
The telephone is a technology of communication that makes it possible for people to talk directly to someone else in a different place.
可能用到的题目：
Telephone has had greater effects on people's lives than television.
“电视”定义：
Television, a communicative medium sending and receiving pictures and sounds by electrical signals, has become a traditional form of mass media and part of the modern culture.
可能用到的题目：
The purpose of television should be all educative, not entertaining.
“电影”定义：
Movies, moving pictures that can tell stories or show reality, have become a mainstream form of art and an important way of entertainment.
可能用到的题目：
Movies and TV have more negative effects than positive effects on the way young people behave.
“电子书”定义：
An electronic book refers to a book-length publication in digital form.
可能用到的题目：
In twenty years from now, students will not use printed books anymore.
“旅行”定义：
Travel means one’s moving from a familiar place to another or to several places.
可能用到的题目：
Which way is the best for students to make new friends: joining a sport team, participating in community activities, or travelling?
托福写作