补充43和72求教

43. The United States petroleum industry’s cost to meet environmental regulations is projected at ten percent of the price per barrel of refined petroleum by the end of the decade.
(A) The United States petroleum industry’s cost to meet environmental regulations is projected at ten percent of the price per barrel of refined petroleum by the end of the decade.
(B) The United States petroleum industry’s cost by the end of the decade to meet environmental regulations is estimated at ten percent of the price per barrel of refined petroleum.
(C) By the end of the decade, the United States petroleum industry’s cost of meeting environmental regulations is projected at ten percent of the price per barrel of refined petroleum.
(D) To meet environmental regulations, the cost to the United States petroleum industry is estimated at ten percent of the price per barrel of refined petroleum by the end of the decade.
(E) It is estimated that by the end of the decade the cost to the United States petroleum industry of meeting environmental regulations will be ten percent of the price per barrel of refined petroleum.

MBA解释43、D，To meet environmental regulations 没有合理的动作行使者，从句子看是the cost ，但这显然不符合逻辑

GMJI的解释43
同意braveMBA 的解释。另外，by the end of the decade也有修饰is estimated 也就是作主句状语的嫌疑。

以上是两个NN的解释,我想请教几个问题:1、如果不定式位于句首是不是也有逻辑主语一说,就象分词位于句首?

2、介词短语是我头疼的问题，C选项中的By the end of the decade 我是否可以理解成修饰了 is projected 即做全句状语；我可不可以理解成它主要是修饰了谓语？如果可以那它和把by the end of the decade直接放在is projected一样的效果？
E中的by the end of the decade是修饰COST吗？关于介词短语的修饰郁闷中，希望NN能给我一个详细的回答，感谢感谢了！

72. Although Ms. Bakara had previously emphasized that she could not speak for other Black people, she ventured to do so on this one occasion because she firmly believed that many minority people, likely most, would agree with her.
(A) do so on this one occasion because she firmly believed that many minority people, likely most, would agree
(B) speak on this one occasion since she firmly believed that many minority people, likely most, would have agreed
(C) so speak on this one occasion due to her firmly believing that many minority people, even most, would likely agree
(D) do so on this one occasion because she firmly believed that many minority people, if not most, would agree
(E) do so on this one occasion since she firmly believed many minority people, and even most, would likely agree

这题是虚拟语气吗？if not most,以前都没见过，怎么解释和理解啊？               

43 - 不定式在句首一般要求逻辑主语明确，类似现分，但是有些情况例外，比如：To do sth is to do sth.可能就不出现主语；介词短语，尤其是表时间的介词短语大都作状语修饰句子(也可理解为修饰谓语动词)，但也有少数作定语修饰名词的。你所举的C和E，介短都是作状语修饰句子的；至于是否可以和动词放在一起，那要看修饰是否会引起混乱，如我上述所言，如果有可能被理解为可以修饰名词，那么这种放法就不可行，但是，OG中有过明确指出，时间状语放在句首是修饰整个句子的，可能这是ETS的一种倾向。

72 - if可以引导让步，解释为：即使；这句话的意思是：她相信许多少数民族的人，即便不是大多数，可能会赞成她；if not most解释为：即便不是大多数，most在这里作形容词。