大学英语六级改错指导：平行结构

平行结构错误主要指在并列连接词and前后语法结构不对等、不平行。其它并列连词还有but, as well as, or, or else, both … and, neither … nor, either … or, not only … but (also)等可连接两个对等的词和对等的结构。

考点例析
1：Computeranalyzed marketing reports can help deciding
which products to emphasize now,which to develop for
the future,　and which to be dropped.? ____________
解析：本句中三个平行成份which products to emphasize now, which to develop和which to be dropped结构模式应该一致，均采用不定式主动语态，因而to be dropped应改为to drop。（注：在四六级考试中，短文改错只能修改、删除或添加一个单词，不能同时改动两个。本例题旨在反映平行结构的语法性质。）
例2：At the heart of the NEA survey is the belief that our
democratic System depends on leaders who can think
critically, analyze texts and writing clearly. ___________
解析：can后面有三个并列的谓语动词，因此writing应改成与think, analyze并列的动词原形write。

例3：Atrophy is a decrease in size of a cell, organ, tissues, or other part of the body. _______
解析;：并列连词or连接四项名词结构，其中cell 和organ皆为单数形式，故tissues应改为单数tissue。