重点讲解
　　本期重点： 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。
改错练习
　　巩固与拓展

　　1.A majority of the reports received from people claiming

　　to have seen the lengendaiy Loch Ness monster have

　　proven to be mistakes, misconceptions, or tricked. ___________

　　2. Your semester grade is based not only on how well you

　　do on each test, but also how you participate in class. ___________

　　3. Modern sience was born when Galileo began trying to explain

　　how things happen and thus originating the method of controlled __________

　　experiment which now forms the basis of scientific investigation

　　4. Restrict your self to one or two pages, and listing ___________

　　any publications or referees on a separate sheet.

　　5. The House proposal would have barred the federal

　　government from demanding library records, read lists, __________

　　book customer lists and other material in terrorism and

　　intelligence investigations.

　　综合改错

　　The biggest safety threat facing airlines today may not be a terrorist

　　With a gun, than the man with the portable computer in business class. 1._____

　　In the last 15 years, pilots report well over 100 incidents tha could 2. _____

　　have been caused by electromagnetic interference. The source of this

　　interference remains confirmed, but increasingly, experts are pointing the 3._____

　　blame at portable electronic devices such as portable computers, radio and 4. _____

　　cassette players and mobile telephones.

　　RTCA, an organization advertises the aviation industry, has 5. ______

　　recommended that the airline bans such devices from 6.______

　　used during “critical” stages of lignt, particularly take-off and landing. 7._______

　　Some experts have gone further, calling for a total ban during all flights.

　　Currently, rules on using these devices are left up to individual airlines.

　　And although some airlines prohibit passengers from using such equipment

　　during take-off and landing, most are willing to enforce a total ban, given 8. ______

　　that many pasengers want to work during flights.

　　The difficulty is predicting how electromagnetic fields may affect an

　　aircraft’s computers. Experts know that portable devices emit radiation

　　which affect those wavelength which craft use for navigation and 9.______

　　communication. But , because they have not been able to reproduce

　　these effects in a laboratory, they have no way of knowing

　　whether the interference might be danger or not. 10.______
参考答案及解析
　　参考答案及解析

　　巩固与拓展

　　1. tricked -> tricks
　　并列连词or连接三项成分。前两项均为名词，故tricked应改为名词tricks与前面的mistakes和misconceptions平行。

　　2. how前加on

　　3. originating -> originated
　　And后面的thus说明并列句的第二部分是和前面的began对应，而非与trying对应。

　　4. listing -> list
　　这句是祈使句，list与前面的restrict并列。

　　5. read -> reading

　　综合练习

　　1. than -> but
　　此处为固定句式not…but…，此句大意为“最大的飞行隐患不是持枪的恐怖分子，而是商务舱中携带手提电脑的人。”

　　2. report-> reported
　　该句子的时间状语是In the last 15 years表明其基本时态是一般过去时。

　　3. confirmed -> unconfirmed
　　根据上下文，电脑对飞机影响的原因还不大清楚，故使用unconfirmed。

　　4. radio -> radios

　　5. organization后加which
　　本句主语是RTCA，谓语是has recommended，中间的an organization advertises the aviation industry是RTCA的同位语，所以advertises the aviation industry应该是做定语修饰organization。故在organization后加which。

　　6. bans -> ban
　　recommend后面的宾语从句要使用虚拟语气，形式为(should) + v，should可省略。

　　7. used前加being
　　From是介词，后面不能直接使用过去分词used，如果要表示相同的意思，要是用动名词形式才行。又因为devices与use之间是被动关系，所以应该加上being。

　　8. willing -> unwilling / reluctant或在willing前加not
　　此句的正确意思是：尽管一些航空公司禁止乘客在飞机起飞和着陆时使用那些电子产品，但由于许多乘客很想在飞行时继续办公，所以很多航空公司也不愿意彻底实施禁令。

　　9.affect -> affects
　　定语从句先行词radiation是单数，从句的谓语动词也要用单数。

　　10. danger -> dangerous