3.逻辑错误.这种错误一般得根据上下文判断得出,分析这么多年六级改错的逻辑错误,答案无一例外都是将文中某个用错的词（很多情况下是一个形容词）改成它的反义词或添上一个否定词,这里要求同学们掌握一些常用的否定词缀,如in-,un-等等,因为有的形容词加上否定词缀就变成了它的反义词,举例如下:

　　（1）the leaders of our country are unconsciously sending the message that reading may be connected to desirable activities that…（07年1月新六级改错第七题）desirable>undesirable

　　（2）The task of learning facts and concepts, one at a time, makes learning laborious, boring and efficient.

　　（07年1月老六级改错第八题）efficient> inefficient.本题中efficient和laborious与boring并列,根据并列成分意思一致原则,也可以推断出这里的efficient应该换成它的反义词.

　　（3）But in the Information Age, no one can get by with knowing how to read well and understand increasingly complex material.（06年6月六级改错第十题）with>without.这里句子主语用了no one表示否定,而整个句子表示肯定的意思,所以后面必然要用一个否定词without与no one构成双重否定表示肯定。

　　（4）Initial impressions are vital, and a badly presented CV could mean acceptance, regardless of what's in it.（06年1月六级改错第三题）acceptance>rejection

　　（5）the person who is unfamiliar with the arts, music,literature, philosophy, or history.（04年6月六级改错第六题） unfamiliar>familiar

　　（6）Except for relatively-isolated trouble spots like present-day Somalia, and occasional years of good harvests, the world's food crisis has remained just around the corner.（04年1月六级改错第四题）good>poor/bad

　　（7）Get someone to check for spelling and grammatic-al errors, because a spell-checker will pick up every mistake.（06年1月六级改错第6题）根据上下文,这里应该表示“不能挑出每个错误”，所以在pick up之前要加上否定词not.