想要问一个语法知识点，求大神解答

5Day

Discussion of greenhouse effects have usually had as a focus the possibility of Earth growing warmer and to what extent it might, but climatologists have indicated all along that precipitation, storminess, and temperature extremes are likely to have the greatest impact on people.

(A) Discussion of greenhouse effects have usually had as a focus the possibility of Earth growing warmer and to what extent it might,
(B) Discussion of greenhouse effects has usually had as its focus whether Earth would get warmer and what the extent would be,
(C) Discussion of greenhouse effects has usually focused on whether Earth would grow warmer and to what extent,
(D) The discussion of greenhouse effects have usually focused on the possibility of Earth getting warmer and to wht extent it might,
(E) The discussion of greenhouse effects has usually focused on whether Earth would grow warmer and the extent that is,
首先第一，建议楼主贴出完整的题目和答案。正确答案是C。

句子前半部分就是focus 做名词还是还是动词而已，五个选项都是对的。那就看focus/had的宾语是什么就好了。下面是每个选项的分析，根据平行原则， 要选B或C。
A. 名词possibility和what从句
B. whether从句和what从句
C. whether从句和what从句
D. 名词possibility和what从句
E. whether从句和名词extent（that是定语从句，修饰extent而已）

BC的区别就是楼主的问题。to some extent是指某种程度上，一般做程度状语。B中what the extent would be结构看起来没错，但实际上不知道具体动作是什么。我个人觉得可以用how warm it could be 或者what level it could get.
C中结构正确，to what extent引导。这里实际上不是倒装。what 在句子中可以充当成分，这里也是，也不存在介词前置。所以这个就是正常的句子顺序。举个栗子：May I know what is your name? what引导了know的宾语从句，是从句中的主语。

如果有遗漏，欢迎其他人指正补充！！

5Day

haimianbaobb 发表于 2020-3-16 07:54
首先感谢您的指正，下次会记得把题目选项也贴出来哒～
然后就是我还是不怎么理解C选项的那个to what exte ...

我学艺不精，这个语法成分我也不太确定。我大放厥词，猜测what这里相当于充当了一个先行词[noun]和关系代词的作用，或许改写为to the extent that/which it might reach能稍微看得清楚些。