答案解析

　　A. not produced by…but that搭配错误。

　　B. not by…but swarms搭配错误;but instead语义重复;that位置错误，使得状语over millions

　　

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　　of years修饰对象不清。

　　C. not by…but搭配错误。

　　D. correct。Not by…but by正确。

　　E:错误同A

　　引申点：

　　平行结构(parallelis)

　　not…but…后面要平行，如not by…but by

　　4. like the grassy fields and old pastures that the upland sandpiper needs for feeding and nesting when it returns in May after wintering in the Argentine Pampas, the sandpipers vanishing in the northeastern United States is a result of residential and industrial development and of changes in farming practices.

　　A. the sandpipers vanishing in the northeastern United States is a result of residential and industrial development and of changes in

　　B. the bird itself is vanishing in the northeastern United States as a result of residential and industrial development and of changes in

　　C. that the birds themselves are vanishing in the northeastern United States is due to residential and industrial development and changes to

　　D. in the northeastern United States, sandpipers’ vanishing is due to residential and industrial development and to changes in

　　E. in the northeastern United States, the sandpipers’ vanishing, a result of residential and industrial development and changing

　　答案解析：

　　A. the sandpipers vanishing不是一个result。

　　B. correct。

　　C. that引导的名词性从句描述的是一个事件与the grassy fields and old pastures不对等。

　　D. sandpipers’ vanishing事件与the grassy fields and old pastures不对等。由于like/unlike的比较相对严格，所以比较对 象应尽可能接近，所以把in the northeastern United States放在中间很awkward。

　　E. the sandpipers’ vanishing事件与the grassy fields and old pastures不对等;主句不完整，缺少谓语; development与changes平行，不与practices平行。

　　引申：

　　1. 比较：like/unlike的对比双方需要遵循严格词性、功能等的平行。

　　2. Due to可以用attributed to或caused by替代来权衡逻辑上是否合理，其次due to，similar to，differing from等有形容 词性质的介词，GMAT中一般不能出现在句首。

　　5. A scrub jay can remember when it cached a particular piece of food in a particular place, researchers have discovered, and tend not to bother to recover a perishable treat if stored long enough to have rotted.

　　A. tend not to bother to recover a perishable treat if

　　B. they tend not to bother recovering a perishable treat

　　C. tending not to bother to recover a perishable treat it

　　D. tends not to bother recovering a perishable treat

　　

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　　E.tends not bothering to recover a perishable treat it

　　答案解析：

　　A. tend单复数错误，应为单数，对应主语 A scrub jay;if从句缺主语。即便加入代词it，也将会荒谬的指代jay，而 不是treat。Bother to do/bother doing都是对的。

　　B. they指代不明。

　　C. 少谓语，It多余。

　　D. Correct。tends使用正确，主谓一致。bother doing用法idiomatic, stored后置定语修饰treat正确。

　　E. tends使用正确，和can remember 并列。tend doing没有这种用法。It多余。

　　引申点：

　　主谓一致(Agreement)，平行对称(Parallelism)

　　1. 主谓一致

　　2. 固定搭配：

　　Tend用法

　　Tend to do sth -- If something tends to happen, it happens often and is likely to happen again

　　Tend to sb/sth 照顾

　　6. Not only did the systematic clearing of forests in the United States create farmland (especially in the Northeast) and gave consumers relatively inexpensive houses and furniture, but it also caused erosion and very quickly deforested whole regions.

　　A. Not only did the systematic clearing of forests in the United States create farmland (especially in the Northeast) and gave consumers relatively inexpensive houses and furniture, but it also

　　B. Not only did the systematic clearing of forests in the United States create farmland (especially in the Northeast), which gave consumers relatively inexpensive houses and furniture, but also

　　C. The systematic clearing of forests in the United States, creating farmland (especially in the Northeast) and giving consumers relatively inexpensive houses and furniture, but also

　　D. The systematic clearing of forests in the United States created farmland (especially in the Northeast) and gave consumers relatively inexpensive houses and furniture, but it also

　　E. The systematic clearing of forests in the United States not only created farmland (especially in the Northeast), giving consumers’ relatively inexpensive houses and furniture, but it

　　答案解析：

　　A. not only 位于句首时，所引导的句子要用倒装，give 和 create 是 and 连接的两个并列成分，而时态已经被 did 提 前，只能用原形。所以这里 gave 错。But it also 没有错。

　　B. Which 定语从句修饰 farmland，逻辑意义错误，是 systematic clearing 给了 consumers houses and furniture，不是farmland。

　　C. But also 之前无谓语，片段。

　　D. Correct;But it also,转折前后句，说明 systematic clearing 既带来了好东西，也带了坏东西，also 的使用，精妙。

　　E. Giving 修饰 created,改变了原来的句意：并列的两个动作;Not only…but…也可以.

　　7. The commission’s office of compliance, inspections, and investigations plans to intensify its scrutiny of stock analysts to investigate not only whether research is an independent function