请教大家一个to do用法的问题

pennyconan

“用不定式位于句尾，使用逗号与前句隔开――这种结构是一种错误的结构。”

是不是少了一个“不”字。。。
斑竹大人到，问题都解决~
我倒是觉得这个问题没有那么绝对，就像斑竹大人所说，其实还要看逻辑和通顺的问题。。。

aeoluseros

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aeoluseros

“用不定式位于句尾，使用逗号与前句隔开――这种结构是一种错误的结构。”

是不是少了一个“不”字。。。
斑竹大人到，问题都解决~
我倒是觉得这个问题没有那么绝对，就像斑竹大人所说，其实还要看逻辑和通顺的问题。。。

-- by 会员 pennyconan (2010/5/5 10:43:42)

umm...当时总结那个帖子的时候犯了错了，以为不能用逗号与前句隔开。
不隔开绝对是可以的，不定式做目的状语很多都直接接在后面修饰前面的谓语动词。
不过现在已经修改了原帖。

AmyGMAT

再补充个句子：
大全473.    Lawmakers are examining measures that would require banks to disclose all fees and account requirements in writing, to providefree cashing of government checks, and to create basic savings accounts that carry minimal fees and require minimal initial deposits.
-- by 会员 aeoluseros (2010/5/5 10:49:56)

斑斑 偶个人认为这个例子不是很符合~这句话不是我们讨论的问题，这只是三个不定时的平行。

我想了想斑斑一开始的回复觉得灰常灰常有道理
那道题的关键就是在于有probably
我还是觉得这种结构“SVO，to do”表目的的不定时前面不能出现逗号，这个规定还是应该严格遵守的吧，因为我看OG prep这些比较权威的参考都是这么给出的
而probably那道题和他们不是很一样，就像斑斑说的probably再这里是一种强调，如果不用逗号隔开就显得有点生硬，而且从语感上也不是很适合。

不是很成熟的想法，请指正！

aeoluseros

you're right. I picked a wrong case.
Amy的说法很有道理。我回去以后也再找找看OG里面你说的那个题再下结论。以前翻过很多语法书没有提到前面能不能出现逗号，问了个外文老师说可以，但是对方接受的语法体系没有GMAT严格，考GMAT家的考试还是需要从GMAT里面找规律…

aeoluseros

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。

AmyGMAT

斑斑 我觉得我们可能都搞混了一个概念
其实正确的说法应该是这样子的
我还是觉得你举这个例子不是很合适，首先我认为你原来总结的那一点有一点疏漏


三、不定式用法的注意点：
1、不定式不能单独在句末做修饰成分（此观点过于绝对，但有参考价值，还是留着不删了，仍待讨论）不定式单独在句末做修饰成分是可以接受的，应该是表示目的的不定式不能单独在句末做修饰成分  就是说SVO，to do如果错的话是有个前提的to do做目的状语。
例：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
而斑斑在上面举得那个例子
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

这里OG没有说to do不可以用，只是unidiomatic，unclear是因为这里to lead不是表示目的，根据前句话的意思后面应该是描述一种结果，应该用leading更好，更符合习惯。

哎，还是偶发帖子说的话不严谨误导大家，

我想这样说是不是应该更合适一些？

SVO，to do 这种用法有时候也是可以接受的

但是当to do是表示目的的不定式状语，则一定是错误的。错误的原因在于不完整，就像上面那道题应该是used to do

而prep2-13      on  its wings ，probably to help it  。这里是不是把probably看做是插入语比较合适，所以把its wings to help it给隔开了

AmyGMAT

新东方老师又给总结过一点
to do的位置
to do在句首 to do，SVO 正确
SVO+to do 正确
SVO，to do 错误

我又想了想我们找到的那些题，还是跟最后那个公式符合的
“，to protect” 错了 因为不定式单独出现了
“，probably to help it”对了 因为前面有probably
“，to lead”错了 因为不定式单独出现了

我觉得斑斑原来那个帖子不用改了，强调一下“不能单独”是不是就可以了？
为了保险是不是在加上“如果是表示目的的不定式状语，这样的用法一定错”

才疏学浅，还是斑斑来斟酌啊~！

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”。

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