求教verbal一题，to do 能否做主语？还有对官方解释的不明白，在线等，急急急

ivansmile33

27题：Obtaining an investment-grade rating will keep the county's future borrowing costs low, protect its already-tattered image, and increase its ability to buy bond insurance.

(A) Obtaining an investment-grade rating will keep the county's future borrowing costs low, protect
(B) To obtain an investment-grade rating will keep the county's future borrowing costs low, and protect
(C) Having obtained an investment-grade rating will, in keeping the county's future borrowing costs low, protect
(D) To obtain an investment-grade rating would keep the county's future borrowing costs low, protecting
(E) Obtaining an investment-grade rating, keeping the county's borrowing costs low, would be protecting


这题疑问是：像我知道是ing能做主语，可是to do能做主语么，读起来很不通顺，而且像官方对B 的解释是：to obtain suggests that obtaining an investment grade rating is an objective in and of itself，not a means to achieve the desired benefits

前一句解释我的理解就是to do 不能做主语，我见过的都是 to do sth,完整句子。否则的话todo没修饰的对象，后一句理解的不好，就算to do 是错的，但是to do 也是表达了一种目的，难道不是方法？ing就可以方法？
求各位牛牛的帮助了，我知道 其他选项用别的错误页可以排除，但是就是对todo 有疑问


对了，D选项也有疑问，就是解释说protecting 引导了一形容词短语来描述主句主语，如果todo不能做主语的话，不就没有主语修饰了？然后解释还说，这样就使得increase 变成没有主语的verb，不懂啊不懂啊，求赐教

kiwifoodtown

TO DO做为非谓语中的不定式，是可以充当除谓语外的任何成分的。举些例子吧：
1作主语（放在句首）
To err is human;to forgive is divine.
           （放在句尾）
It is important to inforce law. It is important to hold people accountable for their actions.

2作宾语
I hope to see you again
This company refused to cooperate with us.

3作宾补
They don't allow people to smoke in the theater.

4作定语
I have a letter to write.
She has four children to take care of.

5作状语
Hating people is like burning your own house to get rid of a rat.

6作独立成分
To begin with, on behalf of all of your American guests, I wish to thank you for the incomparable hospitality.
To make a long story short, he is in hospital now.

类似例句很多，也希望各位同学不要死钻偏难题目，缺忽略了些正常的英语表达方式。

ivansmile33

第一次问问题就有人回复，激动啦~~~能不能麻烦看看我刚刚发的另外一个问题呢？那个问题我也很困惑

sisichen666

对哦  是说肿么看着不顺眼................谢谢啊谢谢啊

加你好友了，加我一个呗.........

-- by 会员 ivansmile33 (2012/9/25 21:42:44)

你这一不顺眼。。。。。看把LS那个NN急的~~

ivansmile33

对哦  是说肿么看着不顺眼................谢谢啊谢谢啊

加你好友了，加我一个呗.........

sisichen666

LZ原来是把过分和现分放句首修饰主句逻辑主语，和to do放句首给弄混了~~~~两种是完全不同的类型。。。v-ing、v-ed放于句首是主句主语放出的动作。。。。而to do句首，是表达一个前提条件，不是修饰关系~~~~

ivansmile33

嗯，是说todo就是一个状语......

ivansmile33

那如果是ving形式放在句首呢？

HarrisZheng

to do 为什么是修饰S的呢，
to do sth, svo里面，to do sth是表示目的，实质是一个条件状语，不是修饰语。


之所以to do sth is to do……成立是因为第一个to do表示目的，第二个to do表示方式。

-- by 会员 维以不永伤6 (2012/9/25 20:50:38)

点评的很好，很多同学还老是问，ving，ved是不是修饰主语。状语从来不能修饰名词，只能修饰动词，或者修饰全句。

-- by 会员 HarrisZheng (2012/9/25 20:57:41)

曼哈顿里不是说to do和不加逗号的ing修饰名词么？
我觉得表示状语的意思和表示todo来修饰后面的主语意思感觉很接近诶？能举出例子说明区别么？谢谢

-- by 会员 ivansmile33 (2012/9/25 20:59:57)

不定式可以做定语  I have some work to finish。 这里就是做定语 修饰work
但你不能生搬硬套。 说白了to do做为非谓语三大形式之一 它可以做句子的任何成分，除了谓语

to do is to do  第一个是主语 第二个是表语
状语的例子 和定语的例子你都已经看过了

sisichen666

to do sth在句首就是表示一个前提条件！！！！为了~~~~和修饰不修饰主语无关！！！~~~