请教大家一个to do用法的问题

AmyGMAT

请教大家一个to do用法的问题
具体的题目我找不到了，但是我记得包括OG上都有这样的解释：to do不定式之前不可以有逗号，即SVO，to do这样的用法是错误的
但是在做题的时候偶尔也会碰到这样的用法
所以我想请教各位nn，上面所说的有上面前提吗？
比如prep2-13
One of the earliestknown birds with a beak and contour feathers, Confuciusornis sanctus, with largeclawlike “thumbs” on its wings, which probably helped them to climb upto a launching position for flight.
A. with large clawlike “thumbs” on its wings,which probably helped them to
B. with large clawlike “thumbs” on their wings,which probably helped it to
C. had large clawlike “thumbs” on its wings, whichprobably helped them
D. had large clawlike “thumbs” on its wings, probably to help it 正确
E. had large clawlike “thumbs” on their wings,probably to help it

D项就用了“，to do”的形式这里不是很明白，是这里用法比较特殊吗？
请指教！

superbat28

我推测，主系表的系动词不是be的时候，用逗号加ving就不适合理解成定语，因为这个时候理解成定语还是状语句意大不相同。

-- by 会员 抓抓sandra (2011/8/20 7:55:03)

给个例子？~主系表，系动词不是be还能是什么~~？appear,smell这些词？
可是如果是这些词的话，后面是adj啊，比如She appears good. 就算句尾有【逗号，ing】形式，这个也不可能定语啊，前头没名词。
抓抓想的是什么情况？我一时没反应过来……

抓抓sandra

我推测，主系表的系动词不是be的时候，用逗号加ving就不适合理解成定语，因为这个时候理解成定语还是状语句意大不相同。

抓抓sandra

bat，小花狐，
我觉得这个protecting应该理解成状语or定语都是可以说得通的，因为这个protecting是主语shields的动作，也是items的功能（因为shields were items，二者相同），而不是主语动作的伴随。我之前的理解是“主系表，ing”的ing并不是一定要是状语，句末逗号隔开的ving完全可以当做定语，只要不会发生歧义即可。比如这里，理解成状语或者定语，一点都不影响句子的逻辑含义，所以可以。

小花呱

我觉得这个补充说明这个点，感觉不是那么准确。
-ing在句末，前面有逗号时，首先的作用是对前面的词进行修饰。 如果前面是个非名词的时候将转为考虑是否是做状语，（伴随或者结果。伴随要求的是和句子主语一致。）
这道题的Protecting 应该是对前面的items of military equipment修饰。
这个用法比如og12-21(D )，og12-38, og12-55(D) 等。

superbat28

to 小花呱，我不知道你这个protecting的问题明白没有~我就在这里再说下好啦~

ing结构前面有逗号的时候，优先考虑其作状语，其修饰的对象是前面整个句子主干。但ing做状语又有很多种区分：
若主句是主系表结构，ing结构是对前面主系表结构的句子做的一种补充说明，此时ing结构不表伴随，不表结果，只是表示一个补充说明的  意思。

而当前面是主谓宾的时候，逗号+ing形式可做伴随动作，可做结果状语。若表伴随，其伴随的是主句动词，但必须保证主句主语是ing形式的动作发出者。若表结果状语，其修饰前面整个主句，并无逻辑主语的问题，但是前面主句再改作名词结构后，可以作为ing结构动作的发出者。举例如下(OG12 Q47)：
Five sea eagles left their nests in western Scotland, bringing to 34.... (这道题是OG最经典的bringing做结果状语，修饰前面整件事)
把主句变为名词，即是The leave of the five sea eagles brings....  可见是这个leave这个事情（把left名词化）作为brings的真正主语。

关于蓝色字体中，是曼哈顿上给出的一种说法~我觉得比较形象和实用，可作为一个辅助的判断标准~

关于to do的问题，我今晚一定要找出个答案~哈哈~

小花呱

OG上找到两个例子：
OG10-34的explanation  Choices C and D are needlessly wordy, and D requires that before North Americans, to be grammatically complete.

这个例子来自解释，而不是原题。

185. The recent surge in the number of airplane flights has clogged the nation's air-traffic control system, to lead to 55 percent more delays at airports, and prompts fears among some officials that safety is being compromised.

(A)to lead to 55 percent more delays at airports, and prompts

(B)leading to 55 percent more delay at airports and prompting

(C)to lead to a 55 percent increase in delay at airports and prompt

(D)to lead to an increase of 55 percent in delaysat airports, and prompted

(E)leading to a 55-percent increase in delays atairports and prompting

OG10的解释：
This question poses two major problems: parallel structure and precision of expression. In E, the best choice, parallel structure is maintained in the participial phrases introduced by leading and prompting, and the phrase 55-percent increase in delays conveys the meaning more accurately than does the phrase 55 percent more delay(s) in A and B. Also, choice A lacks parallelism. In C and D the infinitive phrase to lead to ... is less idiomatic than the participial phrase leading to .. .'_ Choice C uses the singular delay where the plural is needed to indicate an increase in the number of delays; the phrase increase in delay has no exact meaning.


OG11、12的解释：

Parallelism + Diction

The intent of the sentence is to show two effects of the surge in flights. These effects should be stated in parallel ways, instead of the construction to lead ... and prompts ... used in the original sentence. Using participial phrases introduced by leading and prompting solves this problem. The phrase 55 percent more delays is not as clear as the phrase a 55 percent increase in delays.

ATo lead and prompts are not parallel; 55 percent more delays is not clear

B55 percent more delay is unclear

CTo lead and prompt are not parallel; the meaning of increase in delay is not clear

DA participial phrase introduced by leading is preferable to the unclear infinitive phrase to lead to; an increase of 55 percent in delays is awkward and wordy

ECorrect. Leading and prompting are parallel in this sentence; the phrase a 55 percent increase in delays is clear
======================
OG里并没有说to do不可以用，只是说了unclear, unidiomatic，而对于leading也只说了preferable，说明语法上leading和to do都可以，只是用了infinitive phrase造成了含义上的unclear。

不知道这下能否下结论了。但我更为相信“不定式可以在句尾做单独结构”。因为不能在句尾做单独结构并没有很合理的解释，只是当初XDF还是刘振民说出的一个观点，并没有说明本质的evidence。

-- by 会员 aeoluseros (2010/5/6 9:46:15)

斑竹，这个OG12-30
30. For members of the seventeenth-century Ashanti
nation in Africa, animal-hide shields with wooden
frames were essential items of military equipment,
a method to protect warriors against enemy arrows
and spears.



(A) a method to protect

(B) as a method protecting

(C) protecting

(D) as a protection of

(E) to protect
中的E，选项OG给的解释是：although the infinitive to protect would work if it were not preceded by a comma,it cannot act as a nonrestrictive adjectival phrase modifying items.
应该说不定式前加，是不对的。
Ps，我想问问，选项C为什么按照OG的话说可以表示the purpose of the items of military equipment.这点不是说-ing是做主语的伴随状语或者是伴随结果么，那么修饰的应该是animal-hide shields with wooden frames.怎么成了修饰items的目的了呢？？

aeoluseros

嗯，继续观望:-D

AmyGMAT

嗯嗯 似乎是明白了一些，可是现在的问题就是这么多题都没有出现过SVO，to do是正确时候.....
感觉难免缺点说服力
不过总之谨慎吧~
谢谢斑斑

aeoluseros

For members of the seventeenth-century Ashanti nation in Africa, animal-hide shields with wooden frames were essential items of military equipment, a method to protect warriors against enemy arrows and spears.
E to protect
OG的解释是：Choice E is incomplete; used to protect would have been acceptable.
这里to do的形式incomplete就是因为，to protect在这里是表示目的的，表示目的的不定式不可以单独出现在逗号后面。如果加上used就可以接受了。
正确的是protecting

umm..其实这里protecting不是状语，因为前面是主系表结构，独立状语的话是要修饰主谓宾结构的；同理，如果是用to do也是attributive phrase，OG说要加上used是因为“逗号+to do”不能引导attributive phrase来表示事物某一属性，而有了Used就可以引导attributive phrase修饰前面的items of military equipment(或者也可以说是修饰shields，因为是一个东东)。in other words, 依然不可以说明“表示目的的不定式不可以单独出现在逗号后面”。